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Appendix 1 - The Calculation of National Intelligence Levels
Most intelligence tests have been constructed in Britain and the United States and have subsequently been administered to samples of the populations in many other countries throughout the world. From these studies, it is possible to calculate the mean IQs of the populations of 81 nations. In making these calculations, the mean IQ in Britain is set at 100 with a standard deviation of 15 and the mean IQs of other nations is calculated in relation to this yardstick. A factor that needs to be taken into account in making these calculations is that the mean IQs in economically developed nations have been increasing since the 1930s. An adjustment needs to be made for this increase when calculating the mean IQs obtained in countries from tests that were administered some years before or some years later than the British test with which it is being compared. In the case of the Standard Progressive Matrices test, which has been administered in many countries and which we use extensively for the calculation of national IQs, the British mean IQ increased at a rate of approximately 2 IQ points per decade from 1938, when the test was constructed, up to 1979, when the last British standardization on children was carried out (Lynn and Hampson, 1986; Flynn, 1987). Mean IQs on the Wechsler tests increased by approximately 3 IQ points per decade from the mid-1930s to the 1990s (Flynn, 1984, 1998). Where these tests have been used, adjustments for the secular rise of IQs have been made. There are a few studies that have employed tests for which the rate of secular increase in the means is not known. In these cases, we have assumed an increase of 2 IQ points per decade. When the date at which a standardization was carried out is not given, it is assumed to have taken place two years before the date of publication. A problem in estimating some national IQs is that the samples have scored below the first percentile in relation to British norms. The first percentile is equivalent to an IQ of 65. Where national samples have scored below the first percentile, they have been assigned an IQ of 64.

For a number of countries there is more than one study of the national IQ. In these cases, we have averaged the results giving equal weight to each study. These IQs have been calculated and averaged to the nearest whole number.

Argentina
The Progressive Matrices Test was standardized on a sample of 1,680 9- to 15-year-olds over the years of 1942-1946 by Rimoldi (1948). The mean IQ in relation to the British 1979 standardization sample was 86. Adjusting for the 35-year time interval between the two standardizations brings the Argentine IQ up to 93.

Norms for the Coloured Progressive Matrices were collected in 1993 for a sample of 420 5- to 11-year-olds. The data are given by Raven, Raven, and Court (1998). In relation to the 1979 standardization of the British Standard Progressive Matrices, the sample obtained a mean IQ of 101. Due to the 14year interval between the two standardizations, this figure needs to be reduced to 98.

The average of the two results gives an IQ of 96 for Argentina.

Australia
Norms for the American Otis Test were collected about 1936 by McIntyre (1938) on a sample of 35,000 9- to 13-year-olds. The IQ was 95. Because the American Otis Test was standardized in the United States on whites, this needs to be raised to 97.

Norms for the Coloured Progressive Matrices were collected in 1980 for a sample of 5- to 10-year-olds. The data are given by Raven, Court, and Raven (1995). The mean IQ is 98.

Norms for the Standard Progressive Matrices for 8- to 17-year-olds for 1986 are given by Raven, Court, and Raven (1996). In relation to the 1979 British standardization sample, the mean IQ is 100.5. Because of the 7-year interval between the two standardizations, this needs to be reduced to 99. The average of the three studies gives an IQ of 98 for Australia.

Austria
In 1981, the German psychologist, Vinko Buj (1981), published the results of a study in which Cattell's Culture Fair Test was given to representative samples of adults in 21 major European cities and also in Akkra, the capital of Ghana. In this study, the British IQ was 102. Hence the mean IQs in other countries have to be reduced by 2 IQ points to calibrate them to a British IQ of 100. In the case of Austria, the sample of 187 individuals obtained an IQ of 103. To calibrate this IQ against a British IQ of 100, this figure needs to be reduced to 101.

Data for the Standard Progressive Matrices for a sample of 67 13-year-old children tested around 1969 have been reported by Moyles and Wolins (1973). In relation to the 1979 British standardization sample, these children obtained an IQ of 101. Due to the 10-year interval between the two years of data collection, this needs to be raised to 103.

The average of the two results gives an IQ of 102 for Austria.

Barbados
Data for a sample of 108 9- to 15-year-olds were collected for the WISCR by Geller, Ramsey, and Forde (1986) around the year of 1984. They obtained an IQ of 82. Because of the 12-year interval between the two years of data collection, this needs to be reduced to 78.

Belgium
The Coloured Progressive Matrices was standardized in Belgium by Goosens (1952a) on a sample of 944 7- to 13-year-olds. In relation to the 1979 British standardization of the Progressive Matrices, they obtained a mean IQ of 93. Because of the interval of approximately 30 years between the two standardizations, the Belgian IQ needs to be raised to 99.

The Cattell Culture Fair Test was standardized about 1950 on a sample of 920 10- to 16-year-olds by Goosens (1952b). The mean IQ was 104. To equate this IQ to a British IQ of 100, this needs to be reduced to 103.

Buj's sample of 247 obtained a mean IQ of 100. To calibrate this IQ against a British IQ of 100, this figure needs to be reduced to 98. The average of the three studies gives an IQ of 100 for Belgium.

Brazil
Around 1966, data for the Standard Progressive Matrices were collected for a sample of 160 14-year-olds by Natalicio (1968). In relation to the 1979 British standardization sample, the IQ was 85.5. To adjust for the 13-year interval between the two years of data collection, this needs to be raised to 88. The Coloured Progressive Matrices was standardized on a sample of 505 7- to 11-year-olds in 1966, on a sample of 1,131 5- to 11-year-olds in 1982, and on a sample of 1,547 5- to 11-year-olds in 1988. The results of the three data sets are given by Angelini, Alves, Custodio, and Duarte (1988).

In relation to the British norms for the 1979 Standard Progressive Matrices and adjusting for the intervals between the standardizations, the Brazilian children obtained IQs of 84, 90, and 85.

The average of the four results gives an IQ of 87 for Brazil.

Bulgaria
Buj (1981) tested 215 adults with the Culture Fair Test and obtained a mean IQ of 96. This needs to be reduced to 94 to calibrate it against a British mean of 100.

A further standardization of the Cattell Culture Fair Test was carried out in Bulgaria in 1982 and the results were reported by Lynn, Paspalanova, Stetinsky, and Tzenova (1998). The sample consisted of 1,456 11- to 17-year-olds and the mean IQ was 95. This version of the Culture Fair Test was standardized in the United States in 1972, so for the 10-year interval between the two standardizations, the Bulgarian IQ needs to be reduced to 92. To equate this figure with a British IQ of 100, one IQ point needs to be subtracted, bringing the figure to 91. Averaging the two studies gives an IQ of 93 for Bulgaria.

Canada
In 1979, norms for the Standard Progressive Matrices were collected in Canada for a sample of 313 7- to 12-year-olds. The data are given by Raven, Court, and Raven (1996). The mean IQ of the sample is 97.

China
In 1986, norms for the Standard Progressive Matrices were collected in China for a sample of 5,108 5- to 16-year-olds and 18- to 80-year-olds by Zhang. The data are given by Raven, Court, and Raven (1996). For the 5- to 16-year-olds, the mean IQ in relation to the 1979 British standardization sample is 101. Because of the 7-year interval between the two standardizations, this needs to be reduced to 100. For the 18- to 70-year-olds, there are no detailed British norms with which the sample can be compared. Detailed adult American norms are provided by Raven, Court, and Raven (1996) for the year of 1993. These results can be used because the American IQ is 99 in relation to a British IQ of 100. In relation to the American norms, the Chinese sample obtained a mean IQ of 91.5 and in relation to British norms the sample obtained an IQ of 90.5. Because of the 9-year time interal between the two standardizations, this needs to be raised to 92.5. The average of the two data sets is 97.

In 1984, the WISC-R was standardized in China on a sample of 660 6- to 16-year-olds in Shanghai by Li, Jin, Vandenberg, Zhu, and Tang (1990). In relation to the American norms, the Chinese obtained an IQ of 112.4. Because of the 10-year interval between the two standardizations, this needs to be reduced to 109.4. To equate this to a British IQ of 100, this figure needs to be reduced further to 107.4. This sample drawn from Shanghai almost certainly had a higher IQ than that in China as a whole. To adjust for this, we have arbitrarily reduced it by 6 IQ points to give a figure of 103.4.

A study by Li, Sano, and Merwin (1996) compared samples of 297 Chinese and 318 American 14- to 15-year-olds. The Chinese were at schools in and around Beijing and the Americans were at schools in Minneapolis and St. Paul. Six tests were given consisting of verbal and non-verbal reasoning, spatial visualization and spatial rotation, perceptual speed, and arithmetic. On the two reasoning tests combined, the Chinese children obtained an IQ of 103 in relation to an American mean of 100. As noted in our comments on the Stevenson [i]et al.[/i] study in Japan, the IQ in Minneapolis is 5 IQ points higher than in the United States as a whole. However, the Chinese sample drawn from the Beijing schools probably had a higher IQ than that in China as a whole, so we have not made any adjustment for this.

The average of the three studies from China gives an IQ of 100.

Colombia
Results for a sample of 50 13- to 16-year-old white boys attending public schools in the city of Medellin were tested with the Spanish WISC-R around 1998 by Ardila, Pineda, and Rosselli (2000). Their IQ was found to be 98. The Spanish IQ was standardized in Spain in 1991, so to adjust for the 7year interval between the two data collections, the Colombian IQ needs to be reduced to 96. In relation to a British IQ of 100, the Spanish IQ is 99 (see under Spain). Hence, in relation to a British IQ of 100, the IQ of whites in Colombia is estimated to be 95.

The population of Colombia is 20 percent white, 75 percent Native American and Mestizo, and 5 percent black (Philip's World Atlas, 1996). IQs assigned to these groups are 95 for whites, 89 for Native American and Mestizo (as found in Peru, see also under Mexico), and 72 for blacks (as found in Jamaica; see also under Africa). Weighting these IQs by the percentages in the population gives an IQ of 89 for Colombia.

Congo (Brazzaville)
Around 1950, normative data for the Standard Progressive Matrices was collected for a sample of 320 17- to 29-year-olds by Ombredane, Robaye, and Robaye (1952). The mean score was well below the first percentile of the detailed American norms for 1993 given by Raven, Court, and Raven (1996). This sample is therefore assigned an IQ of 64. Because of the 43-year interval between the two years of data collection, this figure is raised to 73.

Data for a sample of 88 13-year-olds at school in Brazzaville tested with the Standard Progressive Matrices around 1992 have been reported by Nkaya, Huteau, and Bonnet (1994). In relation to the 1979 British standardization, their mean IQ is 75. Allowing for the 13-year interval between the two standardizations reduces this figure to 72. The average of the two results gives an IQ of 73 for the Congo (Brazzaville).

Congo (Zaire)
Data for the Progressive Matrices for a sample of 222 10- to 15-year-olds in Katanga have been reported by Laroche (1959). Their scores were below the 1 st percentile of the British 1979 standardization sample, and they have been assigned an IQ of 64. Because of the 20 years between the two years of data collection, this figure has been raised to 68.

Boivin and his colleagues have reported three studies in which the Kaufman Assessment Battery for Children (K-ABC) was administered to children. In the first study, 47 children aged 8 took the test around 1991 and obtained a mean IQ of 65 (Boivin and Giordani, 1993). The K-ABC was standardised in the United States in 1982. This test is similar to the Wechsler tests, and we assume a similar rate of secular increase of 3 IQ points per decade. To adjust for the 9-year interval between the standardization of the K-ABC and the administration of the test in Zaire, the mean of the Zaire sample needs to be reduced by 3 IQ points to 62. In the second study, a sample of 95 7- to 12-year-old children were tested around 1993 and obtained a mean IQ of 71 (Boivin, Giordani, and Bornefeld, 1995). Because of the 10-year interval between the two sets of data, this needs to be reduced to 68. In the third study, a sample of 130 7- to 9-year-olds were tested around 1994 and obtained an IQ of 68 (Giordani, Boivin, Opel, Nseyila, and Lauer, 1996). The 12-year interval between the two data sets requires the reduction of this figure to 65.

The average of the three results is an average IQ for Congo (Zaire) of 65.

Croatia
Around 1952, norms for the Standard Progressive Matrices were collected for a sample of 299 13- to 16-year-olds by Sorokin (1954). In relation to the 1979 British standardization sample, their IQ was 84.5. Because of the 27-year interval between the two standardizations, this needs to be raised to 90.

Cuba
Around 1971, norms for the Standard Progressive Matrices were collected for a sample of 1,144 12- to 18-year-olds by Alonso (1974). In relation to the 1979 British standardization sample, their IQ was 83. To adjust for the 8-year interval between the two standardizations, this needs to be raised to 85.

Czech Republic
Buj's (1981) study of 363 adults tested with the Cattell Culture Fair Test and obtained an IQ of 100. To calibrate this figure against a British IQ of 100, it needs to be reduced to 98.

In 1983, the Coloured Progressive Matrices Test was standardized on a sample of 832 5- to 11-year-olds and the data is provided by Raven, Court, and Raven (1995). In relation to the 1979 British standardization of the Progressive Matrices, the mean IQ is 97. Adjusting for the 4-year time interval between the two standardizations brings the Czech IQ to 96.

The average of the two results gives an IQ of 97 for the Czech Republic.

Denmark
Around 1966, norms for the Standard Progressive Matrices were obtained on a sample of 628 12-year-old children by Vejleskov (1968). Because of the 13-year interval between the two standardizations, this needs to be raised to 97.

In Buj's (1981) study on 122 adults tested with the Cattell Culture Fair Test, the 1Q was 101. To calibrate this figure to a British IQ of 100, it needs to be reduced to 99. The average of the two studies gives an IQ of 98 for Denmark.

Ecuador
Normative data have been collected for the Matrix Analogies Test for a sample of 104 5- to 17-year-olds by Proctor, Kranzler, Rosenbloom, Martinez, and Guevara-Aguire (2000). Their IQ in relation to American Norms was 85. To adjust for the 15-year time period between the two years of data collection, this figure must be reduced to 82. To equate this figure to a British IQ of 100, it needs to be reduced to 80.

Egypt
Data for the Standard Progressive Matrices for a sample of 129 6- to 12-yearolds have been reported by Ahmed (1989). In relation to the 1979 British standardization sample, their IQ was 85. Because of the 12-year interval between the two dates of data collection, this needs to be reduced to 83.

Equatorial Guinea
Around 1984, data for 48 10- to 14-year-olds were collected on the WISC-R (Fernandez-Ballesteros, Juan-Espinoza, Colom, and Calero (1997)). Their IQ was 63. Because of the 12-year interval between the two data collections, this needs to be reduced to 59.

Ethiopia
Around 1989, data for a sample of 250 15-year-old Ethiopian immigrants to Israel tested with the Standard Progressive Matrices have been reported by Kaniel and Fisherman (1991). In relation to the 1979 British standardization sample, their mean IQ was 65.

Because of the 10-year interval between the two collections of data, this needs to be reduced to 63.

Fiji
The population of Fiji is comprised of native Fijians and Indians in approximately equal numbers. Normative data for a sample of 12-year-olds for 76 Fijians and 140 Indians who were tested with the Australian Queensland Test have been published by Chandra (1975). In relation to white Australian children, both ethnic groups in Fiji obtained an IQ of 85. In 1968, the Queensland Test was standardized and the data from Fiji were collected about 1973. To adjust for the 5-year interval between the two years of data collection, the Fijian IQ needs to be reduced to 84.

Finland
In 1970, norms for the Coloured Progressive Matrices were collected by Kyostio (1972) for a sample of 755 7-year-olds drawn from various locations. In relation to the 1979 British standardization, their IQ was 96. Because of the 10-year interval between the two data collections, this needs to be raised to 98.

In Buj's (1981) study in Finland, 120 adults were tested with the Cattell Culture Fair Test and their IQ was 98. To calibrate this figure to a British IQ of 100, this needs to be reduced to 96. The average of the two results gives an IQ of 97 for Finland.

France
Around 1962, the Coloured Progressive Matrices Test was standardized in France by Bourdier (1964) on a sample of 618 6- to 9-year-olds. Their mean IQ was 93.5 in relation to the 1979 British standardization of the Standard Progressive Matrices. Because of the 15-year time interval between the two standardizations, this needs to be increased to 96.5.

Around 1962, the Columbia Mental Maturity Scale was standardized in France on a sample of 328 6- to 11-year-olds by Dague, Garelli, and Lebettre (1964). In relation to the American IQ of 100, the IQ of the French children was 103.5. To adjust for the 3-year interval between the two standardizations, the French IQ needs to be reduced to 102.5

Buj's sample of 1,320 adults obtained a mean IQ of 96 on the Culture Fair Test. Calibration against a British mean IQ of 100 requires the reduction of this figure to 94. The average of the three results gives an IQ of 98 for France.

Germany
Buj's (1981) sample of 1,572 adults in West Germany (the Federal Republic, as it was called at that time) were tested with the Cattell Culture Fair test and obtained a mean IQ of 109. To calibrate this figure against a British mean of 100, it needs to be reduced to 107.

Around 1970, the Coloured Progressive Matrices Test was standardized in West Germany by Winkelman (1972) on a sample of 563 5- to 7-year-olds. The mean IQ in relation to the British standardization sample of the Standard Progressive Matrices is 97. Because of the 9-year interval between the two standardizations, this figure needs to be raised to 99.

In 1978, the Coloured Progressive Matrices Test was standardized again in West Germany on a sample of 3,607 6- to 10-year-olds. The norms are given by Raven, Court, and Raven (1995). In relation to the 1979 British standardization sample of the Standard Progressive Matrices, the IQ of the German sample is 101.

In 1978, norms for the Standard Progressive Matrices were collected for a sample of 2,068 11- to 15-year-olds in West Germany. The data are given by Raven (1981). In relation to the 1979 British standardization sample, the IQ was 105.

Three studies have been made of intelligence in East Germany. In 1967, the Coloured Progressive Matrices Test was standardized in the city of Rostock by Kurth (1969) on a sample of 454 7- to 11-year-olds. Their mean IQ in relation to the 1979 British standardization sample of the Progressive Matrices is 87. Because of the 12-year interval between the two standardizations, this figure needs to be raised to 90.

In 1984, further norms for East Germany were obtained by Guthke and the data are given by Raven, Court, and Raven (1995). The mean IQ of the sample in relation to the 1979 British standardization of the Standard Progressive Matrices is 98. To adjust for the 5-year interval between the two standardizations, this figure needs to be reduced to 97.

Around 1978, norms for the Standard Progressive Matrices were obtained for approximately 1,000 11- to 15-year-olds by Mehlhorn. The data are given by Raven (1981). In relation to the 1979 British standardization sample, their IQ is 99.

The average of the results for West Germany is an IQ of 103 and for East Germany an IQ of 95. For united Germany, weighting these figures by the numbers of the populations of West and East (59.5 million and 16.6 million, respectively), the IQ of united Germany is 102.

Ghana
In the study by Buj (1981), 225 adults in Akkra were tested with the Cattell Culture Fair Test and obtained an IQ of 82. Calibrating this against a British IQ of 100 reduces this figure to 80.

Around 1990, normative data for the Coloured Progressive Matrices was collected for a representative sample of 1,639 adolescents with an average age of 15 by Glewwe and Jacoby (1992). Their mean score corresponded to the zero percentile on the 1979 British standardization sample of the Standard Progressive Matrices and they had an IQ of 64. Because of the 11-year interval between the two standardizations, this needs to be reduced to 62. The average of the two results gives an IQ of 71 for Ghana.

Greece
Around 1961, norms for the Wechsler Intelligence Scale for Children (WISC) were collected for a sample of 400 9- to 14-year-olds by Fatouros (1972). The mean IQ was 91. Because the WISC was standardized on white children, this figure needs to be raised to 93. Adjusting for the interval between the two data collections, this has to be reduced to 88.

The sample of 220 adults tested on the Cattell Culture Fair Test by Buj (1981) obtained an IQ of 97. To calibrate this figure against a British IQ of 100, this needs to be reduced to 95. The average of the two results gives an IQ of 92 for Greece.

Guatemala
Norms have been reported by Johnson, Johnson, and Price-Williams (1967) for the Draw-a-Man Test for a sample of 256 children who were tested around 1965. Their mean IQ was 85. The mean IQ for white American children obtained by Sundberg and Ballinger (1968) at this time was 105. To equate the result to a British IQ of 100, the IQ for Guatemala becomes 79.

Guinea
Around 1933, a sample of 50 village children aged 5- to 14 years was tested with the American Army Performance Scale by Nissen, Machover, and Kinder (1935). Their IQ in relation to the American norms was 61.

A sample of 1,144 young men at technical training centers were tested with the Standard Progressive Matrices in 1951-1955 by Latouche and Dormeau. The results are given by Faverge and Falmagne (1962). The average scores were well below the first percentile of the 15-year-olds in the 1979 British standardization sample and to 18- to 22-year-olds on the American standardization sample. The sample is assigned an IQ of 64. To adjust for the 40 years between the two data collections, the IQ is raised to 70 in relation to a British IQ of 100.

The average of the two results gives an IQ of 66 for Guinea.

Hong Kong
In 1968, data for a sample of 13,822 6- to 13-year-olds who were tested with the Standard Progressive Matrices in 1968 were published by Lynn, Pagliari, and Chan (1988). In relation to the 1979 British standardization sample, their mean IQ was 101.3. In order to adjust for the 11-year interval between the two standardizations, this figure has to be raised to 103.4.

In 1982, a further sample of 4,500 6- to 15-year-olds was tested with the Standard Progressive Matrices. In relation to the 1979 British standardization sample, their mean IQ was 110.4. In order to adjust for the 3-year interval between the two standardizations, this figure needs to be reduced to 110.

Data for a sample of 4,858 6-year-olds who were tested with the Coloured Progressive Matrices during 1981-1984 have been published by Chan and Lynn (1989). In relation to the 1979 British standardization sample, their IQ was 110. Because of the 4-year interval between the two data collections, this needs to be reduced to 109.

A small sample of 197 10-year-olds was tested with the Progressive Matrices in 1986 (Lynn, Pagliari, and Chan, 1988). In relation to the 1979 British standardization sample, their IQ was 108. Because of the 7-year interval between the two years of data collection, this needs to be reduced to 107.

In 1986, a sample of 376 9-year-olds was tested with the Cattell Culture Fair Test (Lynn, Hampson, and Lee, 1988). Their IQ was 113. This version of the Culture Fair Test was standardized in the United States in 1972, so to adjust for the 14-year interval between the two standardizations, the IQ for Hing Kong needs to be reduced to 107.

The average of the five studies gives an IQ of 107 for Hong Kong.

Hungary
The sample of 260 adults tested with the Cattell Culture Fair Test by Buj (1981) obtained an IQ of 101. To calibrate this figure against a British IQ of 100, this needs to be reduced to 99.

India Sinha (1968) summarizes the results of nine studies providing normative data for the Coloured Progressive Matrices for India for a total of 5,607 9- to 15-year-olds. The Indian samples were drawn from Ahmedabad, Trivandrum, Patna, Allahabad, Uttar Pradesh, Cuttack, and Tiru. In relation to the 1979 British standardization sample of the Progressive Matrices, the children of India obtained a mean IQ of 77. There is a time interval of approximately 20 years between the collection of the data in India and Britain, which requires raising the Indian IQ to 81.

A further standardization of the Coloured Progressive Matrices in India was carried out by Rao and Reddy (1968) on a sample of 1,050 5- to 10-year-olds in urban and rural locations in Andhra Pradesh. The mean IQ in relation to the 1979 British standardization of the Progressive Matrices was 80. Adjusting for the 11 years between the two standardizations raises the Indian IQ to 82.

In 1992, norms were collected for the Standard Progressive Matrices for a sample of 569 11- to 15-year-olds in Delhi. The data are given by Raven, Court, and Raven (1996). In relation to the 1979 British standardization sample, the mean IQ is 84. To adjust for the 13-year interval between the two standardizations, this needs to be reduced to 82.

Data for 748 children aged 9 to 12 years old who were tested with the WISC-R have been reported by Afzal (1988). Their mean IQ was 82. Because of the 14-year interval between the standardization of the test and the collection of the data, this needs to be reduced to 78.

The average of the four data sets gives an IQ of 81 for India.

Indonesia
Data for the Draw-a-Man test were collected by Thomas and Sjah (1961) from school children in the city of Bandung. In relation to the 1926 American norms, their IQ was 96. To adjust for the 33 years between the two years of data collection, this figure has been reduced to 89.

Iran
Around 1957, norms for the Standard Progressive Matrices were collected by Valentine (1959) for 627 adolescents aged approximately 15 years old. Their mean IQ in relation to the British 1979 standardization sample is 80. Due to the interval of 22 years between the two standardization samples, this needs to be raised to 84.

Iraq
Around 1968, the Progressive Matrices was standardized in Iraq by Abul-Hubb (1972) on a sample of 204 14- to 17-year-olds and 1,185 adults aged 18- to 35. The mean IQ of the 14- to 17-year-olds in relation to the British 1979 standardization sample is 85. Due to the 10-year interval between the two standardization samples, this needs to be raised to 87. There are no detailed percentile British norms for adults for the Progressive Matrices, but they are given for the United States for the year of 1993 by Raven, Court, and Raven (1996). In relation to these, the mean IQ of the Iraq sample of adults is 85. Because of the 25-year interval between the two standardizations, this needs to be raised to 89. In relation to a British IQ of 100, this needs to be reduce to 87. Averaging the two results gives a mean IQ of 87 for Iraq.

Ireland
In 1972, norms for the Standard Progressive Matrices were obtained for a sample of 3,466 6- to 13-year-olds. The data are given by Raven (1981). In relation to the 1979 British standardization sample, the Irish children obtained a mean IQ of 86. Because the Irish data were collected seven years earlier, this needs to be raised to 87.

In Buj's (1981) study, 75 Adults obtained an IQ of 100 on the Cattell Culture Fair Test. To calibrate this figure against a British IQ of 100, this needs to be reduced to 98. The average of the two studies gives an IQ of 93 for Ireland.

Israel
Around 1975, norms for the American Lorge-Thorndike Test were collected for 180 10- to 12-year-olds by Miron (1977). The mean IQ was 100. In order to adjust for the 11-year interval between the two standardizations, this needs to be reduced to 98. In relation to a British IQ of 100, this needs to be reduced by one further point to 97.

Around 1989, data for the Standard Progressive Matrices for 1,740 9- to 15-year-olds were collected by Kaniel and Fisherman (1991). In relation to the British 1979 standardization sample, their IQ was 92. To adjust for the 10-year interval between the two years of data collection, this needs to be reduced to 90. The average of the results gives an IQ of 94 for Israel.

Italy
Around 1960, norms for the Standard Progressive Matrices were obtained on a sample of 2,432 11- to 16-year-olds by Tesi and Boutourline Young (1962). In relation to the 1979 British standardization norms, the sample obtained an IQ of 99. Because of the 19-year interval between the two standardizations, this needs to be raised to 103.

The sample of 1,380 adults tested with the Culture Fair Test by Buj (1981) obtained an IQ of 103. To calibrate this figure against a British IQ of 100, this needs to be reduced to 101. The average of the two results gives an IQ of 102 for Italy.

Jamaica
In 1961, data for a sample of 1,730 11-year-olds tested with the British Moray House Test were published by Manley (1963). The IQ was 72, in relation to a British mean of 100.

Japan
The first calculation of the IQ in Japan appeared in Lynn (1977a). This paper presented a calculation of the Japanese IQ obtained from the Japanese standardization of the Wechsler Intelligence Scale for Children (WISC). The WISC was standardized in the United States in 1947 and in Japan in 1951. The verbal tests were altered in the Japanese standardization so they could not be used for a comparison, but the performance tests remained the same. On these tests, the Japanese standardization sample obtained an IQ of 103. Because the Japanese standardization was made four years after the American standardization, one IQ point has to be subtracted to give a Japanese IQ of 102. The American standardization was made on whites only, so in relation to the whole American population the Japanese IQ becomes 104. The American IQ in relation to the British IQ of 100 is 98 (see under United States). Thus, in relation to a British IQ of 100, the Japanese IQ becomes 102.

In 1980, a new method for calculating the Japanese IQ was devised (Lynn and Dziobon, 1980). This entailed the administration of the Japanese Kyoto NX test and the American Primary Mental Abilities to a sample of 213 9- to 10-year-olds in Northern Ireland and calibrating the Kyoto test against the American test. The result was that the average Japanese child, with an IQ of 100, obtained an IQ of 110 on the American test, and therefore that the Japanese had an average IQ of 110. Because the Japanese test was standardized in 1972 and the American test was standardized in 1962, adjustment for the 10-year interval between the two standardizations requires the reduction of the Japanese IQ to 108, and to calibrate the Japanese IQ against the British IQ of 100 requires a further reduction to 106.

The next study of the Japanese IQ was made by Misawa, Motegi, Fujita, and Hattori (1984), who analyzed the performance of Japanese children on the American test, the Columbia Mental Maturity Scale. This is a non-verbal reasoning test for 4- to 9-year-olds that was first published in 1954. A revised version and standardization appeared in 1972 and this version was standardized in Japan on a sample of 780 around 1980. The calculation of the Japanese IQ on the test in relation to the American norms shows that the Japanese attained an IQ of 113. Because of the 8-year interval between the two standardizations, this needs to be reduced to 111. To calibrate this IQ against a British IQ of 100, it needs to be reduced further to 109.

In 1985, Stevenson, Stigler, Lee, Lucker, Kitanawa, and Hsu (1985) published a study comparing the IQs of 240 6-year-olds and 240 10-year-olds in the American city of Minneapolis and the Japanese city of Sendai. They constructed their own test consisting of a number of subtests of various abilities. These tests did not include a test of non-verbal reasoning ability such as the Progressive Matrices. It did include a vocabulary test and a spatial test. The results were that in relation to the American children, the Japanese 6-year-olds obtained IQs of 89 on vocabulary and 105 on the spatial test, which can be averaged to 97 for a measure of general intelligence, and the Japanese 11-year-olds obtained IQs of 98 on vocabulary and 107 on the spatial test, which can be averaged to 102. Combining the two results gives a Japanese IQ of 100. This result led Stevenson and his colleagues to conclude that there is no difference between the IQ in Japan and the United States. This study is defective because Minneapolis is not representative for intelligence of American cities. A series of studies have shown that intelligence in the in state of Minnesota, in which Minneapolis is situated, is higher than in the United States as a whole. In the military draft in World War I, whites from Minnesota obtained the highest score on the Army Beta Test out of all American states (Ashley Montagu, 1945) (the scores of blacks are not given). In the draft for the Vietnam war, the percentage of draftees (blacks and whites) who failed the pre-induction mental assessments was the second lowest in Minnesota among the American states (Office of the Surgeon General, 1968, p. 45). On the basis of these data, Flynn (1980) has calculated that the average IQ in Minnesota is 105. Thus, in order to equate the Japanese IQ to that of the United States, 5 IQ points need to be added to the mean of 100 found by Stevenson et al., bringin the IQ to 105. To equate this to a British IQ of 100, one IQ point needs to be subtracted, giving an IQ of approximately 104.

An analysis of the Japanese IQ in terms of the American WISC-R has been made by Lynn and Hampson (1986a). On the Japanese standardization of this test on 1,100 6- to 16-year-olds, the Japanese obtained an IQ of 105. The American test was standardized in 1972 and the Japanese test in 1975, requiring the subtraction of one IQ point from the Japanese mean. To calibrate this figure against a British mean of 100 requires the subtraction of a further 1 point, bringing the Japanese mean to 102.

An analysis of the Japanese IQ in terms of the McCarthy Test has been made by Lynn and Hampson (1986b). The McCarthy Test is for children between the ages of 2.5 and 8.5 years. It was standardized in the United States in 1971 and in Japan in 1975 on a sample of 550 children. In relation to the American standardization sample, the Japanese obtained a mean IQ of 101.7. To adjust for the 4-year interval between the two standardizations, the Japanese mean needs to be reduced to approximately 101. To equate this figure to a British mean of 100, two IQ points need to be subtracted to give a Japanese IQ of 99. This figure is probably lower than the other calculations because half of the test is for young children aged 2.5 to 5.5 years, during which the Japanese children perform poorly when compared with the older age group, suggesting that Japanese children are slow developers during early childhood.

An analysis of the Japanese standardization sample of 600 on the American Wechsler Preschool and Primary Scale, an intelligence test designed for 4- to 6-year-olds, has been made by Lynn and Hampson (1987). Their mean IQ was 107.8. The American test was standardized in 1964 and the Japanese test in 1967. To adjust for the 3-year interval between the two standardizations, the Japanese mean needs to be reduced to 107. To equate this figure to a British mean of 100, two points need to be subtracted, giving a Japanese IQ of 105.

Data for the Standard Progressive Matrices of 444 Japanese 9-year-olds were collected in 1989 by Shigehisa and Lynn (1991). In relation to the 1979 British standardization, their IQ was 112. To adjust for the ten-year interval between the two data collections, this needs to be reduced to 110.

A study by Takeuchi and Scott (1992) reported the performance of a sample of 454 5- to 7-year-old Japanese children in the city of Nagoya on the Canadian Cognitive Abilities Test. The Japanese IQ on the abstract reasoning subtest was 106.9. The Canadian test was standardized around 1989. Because we have estimated the Canadian IQ at 97, three IQ points need to be deducted from the Japanese IQ to calibrate it against a British IQ of 100, bringing the Japanese IQ to 104.

A further study of intelligence in Japan compared with that in the United States has been published by Li, Sano, and Merwin (1996). The samples consisted of 239 14- to 15-year-olds in the Japanese city of Toyama and 318 adolescents of the same age in Minneapolis and St. Paul. Six tests were given including verbal and non-verbal reasoning tests. In relation to an American IQ of 100, the Japanese obtained an IQ of 103. Because the IQ in Minnesota, in which Minneapolis and St. Paul are situated, is 105 (Flynn, 1980), five IQ points need to be added to the Japanese mean to bring it to 108. To equate this figure to a British mean of 100, this needs to be reduced to 106.

The average of the ten calculations of Japanese intelligence gives an IQ of 105.

Kenya
Around 1983, data for the Coloured Progressive Matrices for 205 adults were collected by Boissiere, Knight, and Sabot (1985). In relation to the American 1993 norms for adults, their IQ is 69. Because of the 10-year interval between the two data collections, this needs to be raised to 71. In order to adjust to a British IQ of 100, this needs to be reduced to 69.

Around 1998, norms for the Coloured Progressive Matrices were collected in Kenya on a sample of 1,222 6- to 10-year-olds by Costenbader and Ngari (2000). Their mean IQ in relation to the 1979 British standardization sample of the Progressive Matrices is 79. Adjusting for the 19-year interval between the two standardizations reduces the Kenyan IQ to 75. The average of the two results gives an IQ of 72 for Kenya.

Lebanon
In 1955, data for the Draw-a-Man Test were collected for a sample of 416 5- to 10-year-old children by Dennis (1957). In relation to the 1926 American norms, their IQ was 89. To adjust for the 30-period between the two years of data collection, this has been reduced to 86.

Malaysia
Around 1992, norms for the Standard Progressive Matrices were collected for a sample of 5,412 7- to 12-year-olds by Chaim (1994). In relation to the 1979 British standardization sample, their Iowas 94.5. To adjust for the 13-year interval between the two standardizations, this needs to be reduced to 92.

Marshall Islands
Around 1961, norms were collected for the Cattell Culture Fair Test for a sample of 407 12- to 18-year-olds by Jordheim and Olsen (1963). Their IQ was 87.5. To adjust for the 14-year interval between the year of data collection and the American standardization of the test this needs to be reduced to 84.5. In order to calibrate this figure against a British IQ of 100, this needs to be reduced to 83.5.

Mexico
Around 1961, a study of a sample of 520 6- to 13-year-old Native American and Mestizo children in southern Mexico were tested with the Draw-a-Man test by Modiano (1962). Their mean IQ in relation to American norms of 100 was 86.5. The population of Mexico is 90 percent Native American and Mestizo and 9 percent White (Philip's World Atlas, 1996). We assume that the whites have an IQ of 96, as in Argentina. Combining this estimate with the Modiano study, we obtain an IQ for Mexico of 87.

This result is corroborated by three studies of the IQs of Mexican immigrant children in the United States. Results for a sample of 597 6- to 11-year-old Mexican children in California and described as a representative sample were tested with the Coloured Progressive Matrices in 1972 and the results are given by Raven (1986). In relation to the 1979 British standardization sample, the Mexican children obtained an IQ of 82. Because of the 7-year interval between the two years of data collection, this needs to be raised to 84.

In 1972, data for the Coloured Progressive Matrices were collected for a sample of 434 6- to 11-year-old Mexican American children in Texas and the results are given by Raven (1986). In relation to the 1979 British standardization of the Standard Progressive Matrices, they obtained an IQ of 94. Because of the 7-year interval between the two data collections, this needs to be raised to 95.

Data for the Standard Progressive Matrices were collected for a sample of 404 9- to 12-year-olds in Texas (Raven, 1986). In relation to the British 1979 standardization sample, their IQ was 84.

The average of the three results gives an IQ of 88 for Mexican American children, corroborating the IQ of 87 obtained in the first study from Mexico.

Morocco
A sample of 167 Moroccan immigrants in the Netherlands has been tested with the Dutch General Intelligence Test Battery (Te Nijenhuis and van der Flier, 1997). This test consists of eight subtests measuring verbal, reasoning, numerical, spatial, and perceptual abilities. The Moroccans performed particularly poorly on the vocabulary test, on which they obtained a mean IQ of 69. This low score can be attributed to their poor knowledge of Dutch and has been excluded from the calculation. The mean IQ of the sample on the remaining seven tests in relation to a Dutch mean IQ of 100 is 84.

A further study of the intelligence of Moroccans in the Netherlands has been reported by Flamers, Hessels, and Pennings (1996). This study used a Learning Potential Test, which consists of classification, number series, immediate memory span, figural analogies and the like, and is in effect an intelligence test. The sample consisted of 200 5- to 7-year-olds and obtained an IQ of 85 in relation to a mean of 100 for Dutch children. The average of the two studies gives an IQ of 85 for Morocco.

Nepal
In 1958, normative data were collected for the Draw-a Man Test on a sample of 807 4- to 16-year-olds by Sundberg and Ballinger (1968). They also collected norms for American children. In relation to the American sample, the Nepalese children obtained a mean IQ of 78.

The Netherlands
In Buj's (1981) study of 333 adults tested with the Culture Fair Test, the mean IQ was 109. to calibrate this against a British mean IQ of 100, this needs to be reduced to 107.

In 1984, norms for the Coloured Progressive Matrices were collected by Van Bon and the data are given by Raven, Court, and Raven (1995). The mean IQ in relation to the British 1979 standardization of the standard Progressive Matrices is 99.5. In order to adjust for the 3-year interval between the two standardizations, this figure needs to be reduced to 99.

In 1992, norms for the Standard Progressive Matrices were collected for a sample of 4,032 6- to 12-year-olds. The data are given by Raven, Court, and Raven (1996). In relation to the 1979 British standardization sample, the IQ is 104. Because of the 13-year interval between the two standardizations, this needs to be reduced to 101.

The average of the three results gives an IQ of 102 for the Netherlands.

New Zealand
Around 1938, norms for the American Otis Test were collected by Redmond and Davies (1940) on a sample of 26,000 9- to 15-year-olds. Their IQ was 99.

In 1984, norms for the Coloured Progressive Matrices were collected of 3,108 8- to 17-year-olds by Reid and Gilmore (1989). In relation to the 1979 British standardization, the mean IQ is 102. Because of the 5-year interval between the two standardizations, this needs to be reduced to 101.

The average of the two results gives an IQ of 100 for New Zealand.

Nigeria
In 1965, norms for the Standard Progressive Matrices were collected by Wober (1969) for a sample of 86 adult men. Their mean score was 15.9. This score is well below the bottom of the norm table for British 15-year-olds in the 1979 standardization and for adults in the detailed American norms. terms of the British 1979 standardization, the score of the Nigerian sample is at the level of the average British 6.5-year-old. This sample is assigned an IQ of 64.

Around 1973, data for the Coloured Progressive Matrices for a sample of 375 6- to 13-year-olds were collected by Fahrmeier (1975). In relation to the 1979 British standardization of the Standard Progressive Matrices, the mean IQ is 70. Because of the 6-year interval between the two data collections, this needs to be reduced to 69.

The average of the two results gives an IQ of 67 for Nigeria.

Norway
In Buj's (1981) study, a sample of 100 adults tested with the Carrell Culture Fair test obtained an IQ of 100. To calibrate this to a British IQ of 100., this needs to be reduced to 98.

Peru
In 1993, norms were collected for the Coloured Progressive Matrices on a sample of 4,382 8- to 11-year-old Native American and Mestizo children (Raven, Court, and Raven, 1995). The mean IQ is 90 and is calculated in relation to the 1979 British standardization sample. Adjusting for the 4-year time interval between the two years of data collection brings the Peruvian IQ down to 89. The population of Peru is 88 percent Native American and Mestizo and 12 percent white (Philip's World Atlas, 1996). It is assumed that the whites have an IQ of 95, similar to that of whites in Argentina and Colombia. Weighting by the proportions in the population, the IQ for Peru is estimated at 90.

Philippines
Data have been collected by Flores and Evans (1972) for the Standard Progressive Matrices for 203 children aged 12-13. In relation to the British 1979 standardization sample, their IQ is 86.

Poland
Norms for the Standard Progressive Matrices for a sample of 4,006 6- to 15-year-olds were collected by Jaworowska and and Szustrowa (1991). In relation to the British 1979 standardization sample, their mean IQ is 94. Because of the 10-year interval between the two standardizations, this needs to be reduced to 92.

Buj's (1981) sample of 835 adults tested with Cattell's Culture Fair Test obtained an IQ of 108. To calibrate this figure against a British IQ of 100, it needs to be reduced to 106.

The average of the two studies gives an IQ of 99 for Poland.

Portugal
Buj's sample of 242 adults tested with Cattell's Culture Fair Test obtained an IQ of 103. To calibrate this figure against a British IQ of 100, it needs to be reduced to 101.

Around 1987, norms for the Coloured Progressive Matrices were obtained by Simoes (1989) for a sample of 807 6- to 12-year-olds. In relation to the 1979 British standardization of the Standard Progressive Matrices, their IQ was 90. Because of the 12-year interval between the two standardizations, this needs to be reduced to 88.

The average of the two results gives an IQ of 95 for Portugal.

Puerto Rico
Around 1975, norms were collected for the Coloured Progressive Matrices for a representative sample of 2,400 5- to 11-year-olds. The data are given by Raven, Court, and Raven (1995). In relation to the 1979 standardization of the British Progressive Matrices, their mean IQ is 83.

In 1977, norms for the Standard Progressive Matrices were collected on a representative sample of 2,911 8- to 15-year-olds. The data are given by Raven and Court (1989). In relation to the 1979 British standardization sample, the Puerto Rican IQ was 84. The average of the two results gives an IQ of 84 for Puerto Rico.

Qatar
Norms for the Standard Progressive Matrices were collected for 273 12-year-olds by Bart, Kamal, and Lane (1987). In relation to 1979 British IQ of 100, their IQ is 78.

Romania
Around 1972, norms for the Coloured Progressive Matrices were collected for a sample of 300 6- to 10-year-olds by Zahirnic et al. (1974). In relation to the British 1979 standardization data, the Romanian sample obtained an IQ of 95. Because of the 7-year interval between the two standardizations, this needs to be reduced to 94.

Russia
In 1997, norms for the Standard Progressive Matrices were obtained for a representative sample of 14- to 15-year-olds from Briansk, a city in European Russia about 200 miles southwest of Moscow (Raven, 1998). Their mean IQ in relation to the British standardization sample was 100. Because of the 18-year interval between the two standardizations, this needs to be reduced to 96.

Sierra Leone
Around 1965, data for the Coloured Progressive Matrices for 22 skilled workers aged 23 years old were collected by Binnie-Dawson (1984). The average score of the sample was well below the first percentile of the American 1993 standardization sample. The Sierre Leone sample is assigned an IQ of 64.

Around 1964, data for 60 adults for the Coloured Progressive Matrices were collected by Berry (1966). In relation to the British 1979 standardization sample, their mean IQ was 64.

Both studies give the same result of an IQ of 64 for Sierra Leone.

Singapore
In 1974, data for a representative sample of 147 ethnic Chinese and 190 ethnic Malay 13-year-olds for the Standard Progressive Matrices were collected (Lynn, 19776). In relation to the British 1979 standardization sample, the Chinese obtained a mean IQ of 106 and the Malays a mean IQ of 90.5. Because of the 5-year interval between the two years of data collection, the IQ of the Chinese needs to be increased to 107.5 and the IQ of the Malays needs to be increased to 92. The population of Singapore is 76 percent Chinese, 14 percent Malay, and 7 percent Indian, with the remaining 3 percent being unspecified (Philip's WorldAtlas, 1996). It is assumed that the IQ of the ethnic Indians is 81, the same as that in India. Weighting the IQs of the three IQ groups by their percentages in the population, we arrive at an IQ of 103 for Singapore. Slovakia In 1983, the Coloured Progressive Matrices Test was standardized on a sample of 832 5- to 11-year-olds

Slovakia
In 1983, the Coloured Progressive Matrices Test was standardized on a sample of 832 5- to 11-year-olds and the data are given by Raven, Court, and Raven (1995). In relation to the 1979 British standardization of the Progressive Matrices, the mean IQ of the Slovakian children is 97. Adjusting for the 4-year time interval between the two standardizations brings the Slovakian IQ down to 96.

Slovenia
In 1998, the Standard Progressive Matrices was standardized in Slovenia on a sample of 1,556 8- to 18-year-olds. In relation to the British 1979 standardization sample, their mean IQ was 99. To adjust for the 19 years between the two standardizations, this needs to be reduced to 95.

South Africa
In the 1920s, intelligence test data were collected in South Africa by Fick (1929) who gave the American Army Beta Test — a non-verbal test that was the model for the performance scale of the later Wechsler tests — to samples of 293 10- to 14-year-old Blacks, 762 Indians, and 4,921 Coloreds (who are largely of mixed black-white ancestry). In relation to the American norms collected a few years previously, the Blacks obtained an IQ of 65, the Indians of 77, and the Coloreds of 84.

In 1948, norms for Blacks for the Standard Progressive Matrices were collected by Notcutt (1950) for samples of 1,008 8- to 16-year-olds and 703 adults. In relation to the 1979 British standardization sample, the children obtained a mean IQ of 69. Because of the 31-year interval between the two standardizations, this needs to be raised to 75. The mean score of the adults is well below the bottom of the American norm table for adults provided by Raven, Court, and Raven (1996) and of 15-year-olds in the 1979 standardization sample. In relation to the 1979 British standardization, the mean score of the sample is at the level of the average 7.5-year-old. The sample is assigned an IQ of 64.

Around 1990, further normative data for the Standard Progressive Matrices were collected by Owen (1992) for 16-year-olds of the four major racial and ethnic groups of Whites, Blacks, Indians and Coloreds. In relation to the 1979 British standardization norms, the Whites (N = 1,056) obtained a mean IQ of 96. Because of the 11-year interval between the two standardizations, this needs to be reduced to 94. The mean IQ of the Blacks (N = 1,096) was 69, which needs to be reduced to 67. The mean IQ of the Coloreds (N = 778) was 82, which needs to be reduced to 80. The mean IQ of the Indians (N = 1,063) was 90, which needs to be reduced to 88.

In 1988, further data for the Standard Progressive Matrices were obtained for a sample of 350 Black 9-year-olds by Lynn and Holmshaw (1990). In relation to the 1979 British standardization sample, they obtained an IQ of 65. Because of the 9-year interval between the two data collections, this needs to be reduced to 63.

The averages of these results give the following IQs for the four racial groups — Whites: 94; Blacks: 66; Coloreds: 82; and Indians: 83. The percentages of the four groups in the population are Whites: 14; Blacks: 75; Coloreds: 9; and Indians: 2 (Ramsay, 2000). Weighting the IQs of the four groups by their percentages in the population gives an IQ of 72 for South Africa.

South Korea
In 1986, the Kaufman Assessment Battery for Children (K-ABC) was standardized by Moon (1988) on a sample of 440 2- to 12-year-olds. The KABC contains a test of "simultaneous processing," which is a measure of non-verbal reasoning. The Korean children obtained an IQ of 107.2. The Korean standardization was made five years after the American standardization, for which 1.5 points need to be deducted from the British IQ. To equate the Korean IQ to a British IQ of 100, one more IQ point needs to be deducted, bringing the Korean IQ down to 105.

1992, a study of a sample of 107 9-year-olds was tested with the Standard Progressive Matrices (Lynn and Song, 1994). In relation to the 1979 British standardization sample, their IQ was 109. To adjust for the 13 years between the two data collections, this needs to be reduced to 106.4. The average of the two studies gives an IQ of 106 for South Korea.

Spain
Buj (1981) gives data for 848 adults tested with the Culture Fair Test. Their mean IQ was 100. To calibrate this figure against a British mean of 100, this needs to be reduced to 98.

Around 1992, normative data for the Coloured Progressive Matrices were collected and are given by Raven, Court, and Raven (1995). In relation to the 1979 British standardization of the Standard Progressive Matrices, their mean IQ is 99. To adjust for the 14-year interval between the two standardizations, this needs to be reduced to 96.

Data for the Standard Progressive Matrices for 113,749 military conscripts were reported by Nieto-Alegre, Navarro, Cruz, and Dominguez (1967). The mean IQ was equivalent to 90 on the 1979 British standardization. However, the Spanish conscripts were of a low educational level and were unrepresentative of the population (Colom, Andres-Pueyo, and JuanEspinosa, 1998) and cannot be used.

The average of the two valid studies gives an IQ of 97 for Spain.

Sudan
Data for the Standard Progressive Matrices for a sample of 148 8- to 12-yearolds have been reported by Ahmed (1989). In relation to the 1979 British standardization sample, their mean IQ was 74. To adjust for the 12-year interval between the two years of data collection, this needs to be reduced to 72.

In 1954, a study of the intelligence of 291 children was made by Fahmy (1964). The sample was taken from the west bank of the white Nile, which is "inhabited by the Shilluk, one of the primitive Nilotic Negro tribes" (p.164). The children were given four American tests-the Goddard Formboard, the Porteus Maze, the Alexander Passalong, and the Draw-a-Man Test. Their average IQ was 73.5. The dates of the standardization of the first three of these tests in the United States are not known. This result has therefore not been used, but it provides some confirmation for the Progressive Matrices result, which indicates that the IQ in Sudan is around 72.

Suriname
There are a number of immigrants from this former Dutch colony in the Netherlands. A sample of 535 individuals with a mean age of 30 years has been tested with the Dutch General Aptitude Test Battery by Te Nijenhuis and van der Flier (1997). In relation to a Dutch IQ of 100, their mean IQ was 89.

Sweden
In a standardization of the WISC in Sweden in 1968 on a sample of 1,106 6- to 15-year-olds, the Swedish children obtained an IQ of 104 on the performance scale (Skandinaviska Testforlaget, 1970). Because the WISC was standardized on Whites, this figure needs to be raised to 106. To adjust for the 21-year interval between this and the American standardization, this needs to be reduced to 99. To equate this figure to an IQ of 100 for Britain, this needs to be reduced to 97.

Buj's (1981) sample of 205 adults tested with the Cattell Culture Fair Test obtained an IQ of 106. To calibrate this figure against a British IQ of 100, this needs to be reduced to 104. The average of the two results gives an IQ of 101 for Sweden.

Switzerland
Buj (1981) obtained a mean IQ of 103 on a sample of 163 adults tested with the Cattell Culture Fair Test. To calibrate this figure against a British IQ of 100, this needs to be reduced to 101. The Coloured Progressive Matrices Test has been standardized twice, in 1970 and again in 1989. The data are given by Raven, Court, and Raven (1995). For the 1970 standardization on 6- to 10-year-olds (for which the sample size is not given), the equivalent British IQ derived from the 1979 standardization of the Progressive Matrices is 97. Adjusting for the nine years between the two standardizations brings the Swiss IQ up to 99. On the 1989 Swiss standardization of the Standard Progressive Matrices based on a sample of 167 6- to 10-year-olds, the equivalent British IQ derived from the 1979 standardization sample of the Progressive Matrices is 104. Adjusting for the 10-year time interval between the two standardizations brings the Swiss IQ down to 102.

The average of the three studies gives an IQ of 101 for Switzerland.

Taiwan
Around 1956, data for a sample of 1,290 16-year-olds tested with the Cattell Culture Fair Test were collected by Rodd (1959). In relation to the American norms, their IQ was 105. The test was standardized in the United States in 1947. To adjust for the 9-year interval between the two years of data collection, the Taiwan IQ needs to be reduced to 103. In relation to a British IQ of 100, this needs to be reduced to 101.

In 1975, norms for the Coloured Progressive Matrices were collected by Hsu. (1976) for all first grade children in Taipei, numbering 43,825 and with an average age of 6.8 years. In relation to the 1979 British standardization sample, their IQ was 102.7. Because of the 4-year interval between the two standardizations, this needs to be raised to 103.5

A study by Stevenson et al. (1985) of intelligence in the United States and ... also included the collection of data on a sample of 480 6- and 10-year-olds in Taipei. The authors state that the mean IQ of the Taiwanese children was the same as that of the American. As noted in the summary of this study in our section on Japan, the American sample was drawn from the city of Minneapolis where the IQ is five points higher than that in the United States as a whole. This means that five points need to be added to the Taiwan figure, bringing it to 105.

Norms for the Standard Progressive Matrices were collected in 1989 for a sample of 2,496 9- to 12-year-olds and have been published by Lynn (1997b). The data are given by Raven, Court, and Raven (1996) and have been analyzed by Lynn (1997). In relation to the British 1979 standardization sample, the IQ was 106.6. Because of the 10-year interval between the two standardizations, this needs to be reduced to 105.

The average of the four studies gives an IQ of 104 for Taiwan. Tanzania Around 1965, data for the Standard Progressive Matrices were obtained for a sample of 2,959 secondary school adolescents with an average age of 17 (Klingelhofer, 1967). In relation to the British 1979 standardization sample, their IQ was 75. To adjust for the 14-year interval between the two years of data collection, this needs to be raised to 78.

Around 1983, data for the Coloured Progressive Matrices were obtained for a sample of 179 adults by Boissiere, Knight, and Sabot (1985). Their mean IQ in relation to the 1993 American norms for adults is 65. Because of the 10-year interval between the two data collections, this needs to be raised to 67. In relation to a British IQ of 100, this needs to be reduced to 65.

The average of the two studies gives an IQ of 72 for Tanzania.

Thailand
Data have been collected for the Colored Progressive Matrices for ... to the British 1979 standardization sample, their mean IQ is 91.

Tonga
Data for the Progressive Achievement Test, a test of verbal intelligence measuring reading comprehension and vocabulary, have been reported for 80 8- to 9-year-old ethnically Polynesian children at schools in Auckland, New Zealand. The children's parents came from Western Samoa and Tonga. Their mean IQ was 86 (Beck and St. George, 1983).

In 1984, the Standard Progressive Matrices was normalized in New Zealand on a sample of 3,108 8- to 17-year-olds by Reid and Gilmore (1989). The sample included 65 ethnic Pacific Islanders. Their IQ in relation to the 1979 British standardization sample was 88.5. Because of the 5-year interval between the two standardizations, this needs to be reduced to 87.5. The average of the two studies gives an IQ of 87 for Tonga.

Turkey
Around 1992, the Standard Progressive Matrices was standardized on a sample of 2,277 6- to 15-year-olds by Sahin and Duzen (1994). In relation to the 1979 British standardization sample, their IQ was 93. Because of the 13-year interval between the two standardizations, this needs to be reduced to 90. We adopt this as the best estimate of the IQ in Turkey.

Two corroboration studies are available for samples of Turkish immigrants in the Netherlands. In the first, a sample with a mean age of 24 has been tested with the Dutch General Aptitude Test Battery by Te Nijenhuis and van der Flier (1997). This test consists of eight subtests measuring a range of verbal, reasoning, spatial, and perceptual abilities. The Turkish sample performed exceptionally poorly on the vocabulary subtest. This is attributable to their imperfect knowledge of Dutch and has been discounted. On the remaining seven subtests, they obtained a mean IQ of 88 in relation to a Dutch mean of 100. A further sample of 200 5- to 7-year-old Turkish children in the Netherlands has been tested on the Learning Potential Test by Hamers, Hessels, and Pennings (1996). Their mean IQ in relation to 100 for Dutch children was 85.

Uganda
In 1972, data for the Coloured Progressive Matrices were collected for a representative sample of 2,019 11-year-olds and have been published by Heyneman and Jamison (1980). In relation to the 1979 British standardization of the Standard Progressive Matrices, their IQ was 72. Because of the 7-year interval between the two years of data collection, this needs to be raised to 73.

United States
It first became possible to compare the IQs in the United States and Britain in 1933. In this year, the Scottish Council for Research in Education (1933) published the results of its survey of the intelligence of Scottish children in which a representative sample of 1,000 11-year-olds were tested with the American Stanford Binet. The IQ of the Scottish children was 100. Three adjustments need to be made to this figure. First, the Stanford Binet was standardized in the United States in 1914. To allow for the 18-year interval between the two standardizations, the Scottish IQ must be reduced by five IQ points to 95. Second, the Scottish IQ is 97 in relation to a British IQ of 100 (Lynn, 1979), so 3 IQ points need to be added to this figure to compare the United States with Britain, bringing British IQ to 98. Third, the American Stanford Binet was normalized on whites only. In the United States, the mean IQ of whites is 102.2 in relation to that of the total population (Jensen and Reynolds, 1982). Hence, two IQ points need to be added to the British IQ to calibrate it to an IQ of 100 for the American population that is inclusive of blacks. This brings the IQ in Britain to 100.

In 1949, the publication of the second survey of the intelligence of Scottish children made it possible to make a further comparison of the IQs in the United States and Britain. The second Scottish survey was carried out in 1947, and it included the testing of a representative sample of 1,215 11-yearolds with the American Terman Merrill Test. The mean IQ of the Scottish children was 102.5 (Scottish Council for Research in Education, 1949). As with the first Scottish survey, three adjustments are required. First, the Terman Merrill was standardized in the United States in 1932. Thus, to adjust for the 15-year interval between the two standardizations, 4.5 IQ points need to be subtracted from the Scottish means, bringing it down to 98. Second, the Scottish IQ is three points below the British IQ, so three points need to be added bringing the IQ for Britain up to 101. Third, the American IQ is for whites only. The IQ for the total population is two points lower. This requires adding two points to the British IQ, bringing it up to 103.

The Differential Aptitude Test (DAT) was developed in the United States in 1947 for adolescents aged 13-18. In 1972, it was restandardized on a sample of approximately 64,000. In 1978, the test was standardized in Britain on a sample of approximately 10,000 adolescents (Hodgkiss, 1978). The DAT contains an abstract reasoning test which is taken as the best measure of general intelligence. On this test, the British sample obtained an IQ of 103. Because of the 5-year interval between the two standardizations, the British IQ needs to be reduced to 102.

Norms for the Standard Progressive Matrices for United States for adults aged 18-70 for 1993 are given by Raven, Court, and Raven (1996). In relation to the British 1992 standardization of the test on adults, the American IQ is 98. The average for the four results gives the United States an IQ of 98 in relation to a British IQ of 100.

Uruguay
Around 1957, norms for the Standard Progressive Matrices were collected by Risso (1961) for a sample of 1,634 adolescents and adults. The adolescents obtained an IQ of 89 in relation to the 1979 British standardization sample. Because of the 22-year interval between the two standardizations, this needs to be raised to 93. The adults obtained an IQ of 93 in relation to the 1993 American norms. Because of the 36-year interval between the two standardizations, this needs to be raised to 100. In relation to a British IQ of 100, this needs to be reduced to 98.

The average of the two results gives an IQ of 96 for Uruguay.

Western Samoa
Data for the Progressive Achievement Test, a test of verbal intelligence measuring reading comprehension and vocabulary, have been reported for 80 8- to 9-year-old ethnically Polynesian children at schools in Auckland, New Zealand. The children's parents came from Western Samoa and Tonga. Their mean IQ was 86 (Beck and St. George, 1983).

In 1984, data for 65 Pacific Islander children were obtained in the standardization of the Standard Progressive Matrices in New Zealand by Reid and Gilmore (1989). In relation to the 1979 British standardization sample, their IQ was 88.5. Because of the 5-year interval between the two standardizations this needs to be reduced to 87.5.

The average of the two results gives an IQ of 87 for Western Samoa.

Zambia
In 1962, data for the Standard Progressive Matrices were collected for a representative sample of 759 13-year-olds at school by MacArthur, Irvine, and Brimble (1964). In relation to the 1979 British standardization sample, their IQ was 74. Because of the 17-year interval between the two standardizations, this needs to be raised to 77.

Zimbabwe
Intelligence data for 12- to 14-year-olds taking the WISC-R and the Progressive Matrices have been reported by Zindi (1994). On the WISC-R, the mean IQ of the sample was 67.1. This test was standardized in the United States in 1972. To adjust for the 20-year interval between the two data collections, six IQ points need to be subtracted from the Zimbabwe sample to give an IQ of 61. Zindi states that the sample obtained a mean IQ of 72.4 on the Progressive Matrices, although he does not describe how this figure was calculated or whether the test was the Standard or Coloured version of the test. Because there are no norms for the Coloured Progressive Matrices for 12- to 14-year-olds, it is assumed that the test was the Standard Progressive Matrices. Adjusting for the 13-year interval between the two data collections entails the reduction of the IQ to 70. The average of the two results gives an IQ of 66 for Zimbabwe.