Talk:Life expectancy/Archive 2

Gender differences
"Interestingly, the age of equalization (about 13) tends to be close to the age of menarche, suggesting a potential reproductive-equilibrium explanation. Women, whose reproductive cycle tends to result in regular blood loss, are better-able to cope with blood loss and trauma."

This material was added to the section on gender differences, removed because unsourced and not clear - author wanted to put it back, so moved here for discussion.


 * In addition to providing no WP:MEDRS, no basis/explanation is given for claim that women better-able to cope with blood loss and trauma - in what way, or physiological (rate of platelet/etc. production), what statistics/studies support this claim, etc.
 * The age of menarche has declined in recent years in more developed countries, it isn't clear that "about 13" is typical of humans in general over historical, much less over an evolutionarily relevant time period. Also, when was/is the age equalization at about age 13?  (e.g., did the age of equalization track with the age of menarche).

So if these form part of a widely held opinion, needs clarification, and citations for verification. Zodon (talk) 18:19, 30 January 2009 (UTC)


 * Comment: This is not about a "widely-held opinion." This is about science. Males tend to be born in higher numbers than females, resulting in a gender ratio of about 105:100. At age 13, the ratio is 100:100 (the age of equalization). It makes sense from an evolutionary standpoint for the age of equalization to be around the time that humans begin reproducing. We are talking about the last 100,000 years here. Advances in science may have altered evolutionary trends, but it does not negate the reasons for them. Ryoung 122 03:06, 31 January 2009 (UTC)


 * By widely held opinion I meant a "significant views that have been published by reliable sources."WP:NPOV If it is not a widely held opinion/significant view, then it doesn't belong in the article.  (Sorry if that confused, I didn't remember the particular wording of the policy.)
 * This is about WP:verifiability, and WP:NOR. No source is given for these claims.  As noted the claims are far from self evident and they are missing the detail/context necessary for Wikipedia to provide neutral coverage, and for a reader to understand and evaluate them.
 * It isn't particularly clear that the age of equalization would have anything to do with age of menarche. A population can be sustainable with far fewer breeding males than females. The assumption of lack of death from childbirths also makes the measure highly artificial (death in childbirth are a common limiter of female life expectancy before sanitary technique, etc.).  (If you drop that assumption, men often lived longer than women.)
 * The claimed significance of age of parity also assumes no age difference in mating, that only one male mates with each female, etc. Lots of examples in history and anthropology, as well as examples from other mammals, where these conditions don't hold.  (Older, more powerful, wealthier male having multiple breeding partners, etc.)
 * Until reliable sources are provided for this, these claims should not be in the article. When sources are provided, then needs more explanation/commentary to either make it clear, or to cover the weaknesses in the theory.  Zodon (talk) 10:45, 31 January 2009 (UTC)


 * While researching another article I came across a source that points out some of the problems with the claim about menstruation. Regular blood loss for women was not common before the last hundred years or so. Zodon (talk) 07:15, 5 February 2009 (UTC)
 * Greetings, first of all I was not talking about menstruation only but about CHILD BIRTH. A lot of blood could be lost in child birth; evolution would favor women who bleed less or can cope with more blood loss. Also, re-read your article again...it does NOT say that "regular blood loss for women was not common". It says that the menstrual cycle tended to interrupted far more often by pregnancy and lactation in the past. Ryoung 122 08:02, 5 February 2009 (UTC)


 * The item cited is apropos the claims made above, and could be useful for balance, etc. However I made no changes to the article based on that source. The removal was because the disputed material in the article cites no sources. Zodon (talk) 06:15, 6 February 2009 (UTC)

The claim about menstruation is unusual to say the least, but women have a demonstrated advantage due to doubling up on the X chromosome - there are any number of sex-linked diseases that predominantly affect men. Maybe add a reference to the X-linked recessive page? (77.195.12.163 (talk) 19:55, 3 September 2009 (UTC))

Reversion of organizational changes
This edit reverted several organizational changes without explanation. The changes were explained in edit summaries in the preceding few edits - but to summarize: the section title change was per WP:MOSHEAD, the change from "genetic advantage" to "gender difference" was for neutrality (not clear that genetics is basis of differences, nor which/what is the advantage), the changes of order and wording were to help paragraph flow. All the statistics in the paragraph need citation (where and when do they apply to, etc.), hence the fact tag. Please explain reason for reverting those changes. Thank you. (Discussion of the other change that was reverted is in the section above.) Zodon (talk) 11:33, 31 January 2009 (UTC)


 * Comment: I mass-reverted the article because the changes you made could not be undone individually. The change from "genetic advantage" to "genetic difference" is clearly ridiculous. If females live longer, that is an "advantage" from a numbers-standpoint. There really is no question here about that particular fact. Some people confuse "neutrality" with not being able to state a fact. Did Serena Williams win her match today? Yes she did. If I said that Serena is #1 in the world, is that a fact? Actually, it is.


 * Also, if you want to add "fact" tags, be my guest. However, I do believe that the changes I made significantly improved the section compared to what was there before, and you should give this time to amalgamate before blanket-undo's.


 * If females lived longer because they got in fewer motorcycle wrecks, smoked fewer cigarettes, and ate less hamburgers, then why do females outlive males in the womb? In the nursing home? In the preemie units at the hospital? Clearly, even when environmental factors are removed, females have a life expectancy advantage...one that is gradual, cumulative, and continual...females have a lower death rate at every age on the life insurance table. That can't be explained by environment. Ryoung 122 03:51, 1 February 2009 (UTC)

There is no single "insurance table". The actuaries keep changing them every few years and even the inter-company study tables are different from country to country for a variety of reasons, not always having to do with accuracy. The fact that some unspecified "insurance table" says something is not particularly good evidence that it is true about mortality risks at older ages, either. The amount of life insurance data at older ages is very thin for older persons and the estimates are often made on a per policy basis rather than on a per life basis. Furthermore, the recent analyses of mortality above age 95 suggests that there may be a reversal of the female mortality advantage. I have not chosen to identify myself, but I am a physician with an MPH and have worked in life insurance for 15 years. —Preceding unsigned comment added by 98.217.31.177 (talk) 19:51, 4 October 2009 (UTC)


 * Population mortality tables are more relevant to this than insurance ones, and they contain enough data even at ages above 95 to support firm conclusions about the comparison between male and female mortality rates at those ages. See for instance this link: http://www.statistics.gov.uk/downloads/theme_population/Methodology.pdf          Ehrenkater (talk) 13:02, 5 October 2009 (UTC)


 * Of course my changes could be undone individually. You could re-insert the deleted material, if that was the part of the changes you were trying to undo.  Just as I moved to the talk page just those sections of the material that I found most questionable as to verifiability and POV.
 * I did not make "blanket-undo's." Zodon (talk) 08:50, 1 February 2009 (UTC)


 * Here's a citation:

Clinics Print ISSN 1807-5932 Clinics vol.61 no.5 São Paulo Oct. 2006 doi: 10.1590/S1807-59322006000500017 REVIEW

Gender and sex hormones influence the response to trauma and sepsis – potential therapeutic approaches

Hormônios sexuais influenciam a resposta ao trauma e à sepsis – possíveis soluções terapêuticas

Martin K. AngeleI; Markus C. FrantzII; Irshad H. ChaudryIII

IDepartment of Surgery, Klinikum Grosshadern - Munich, Germany IIENT Department, Klinikum rechts der Isar - München, Germany IIICenter for Surgical Research, Department of Surgery - Birmingham, AL, USA. Email: irshad.chaudry@ccc.uab.edu

Offener et al identified male gender as an independent risk factor for the development of severe infection in surgical patients.

Similar gender-dimorphic findings have been demonstrated in experimental studies following severe blood loss and the induction of sepsis or sepsis-like states (Fig. 1).30-32 Female Wistar rats have been reported to be more resistant to lethal circulatory stress induced by trauma or intestinal ischemia.32 In addition, female mice in the proestrus state of their estrus cycle tolerate sepsis better than male mice as demonstrated by increased survival rates of females following polymicrobial septic challenge (female survival rate 60% compared to 25% in male animals).

http://www.scielo.br/pdf/clin/v61n5/31813.pdf

Note that the gender survival differences were HUGE. Ryoung 122 12:17, 6 February 2009 (UTC)

Some changes
I took away the life expectancy age of the upper class in the calipaths, it was just too absurd. Just look at the caliphes medium life lenght. Awakened82 (talk) 09:57, 28 April 2009 (UTC)

Some possible considerations

 * Please mind the difference between gender(social) and genetic(biological). To claim a genetic sex difference is a determinate of life expectancy is premature considering the contemporary scientific knowledge, this claim would be coincidental and possibly never be provable.  Coincidence may exist between gender and genetic sex.


 * Consider genetic quality in the case of sex ratios and genetic liquidation. A reduction in genetic quality can be associated with a reduction in genetic diversity/variability and indeed the opposite.  The idea of fewer males to females to required sustain a population is a dubious claim when considering populations.  It is possible lack of diversity/variability, acute specialization or disease susceptibility may lead eventually to extinction of the genome population.  Hence population sustenance must go beyond a single generation when genetic information is considered. eg. monoculture(very limited genetic variation/diversity) in agriculture leads to high susceptibility of disease.  —Preceding unsigned comment added by 203.161.69.183 (talk) 12:08, 15 January 2011 (UTC)

Asian and European Life Expectancy
Right now the article says:

"In contrast, Asian-Americans live the longest of all ethnic groups in the United States, with a life expectancy of 87 years, almost ten years longer than Euro-Americans.,[35] which falls in line with the longer life expectancy among East Asian countries globally compared to European, Latin American or African countries."

This is incorrect. The first part is right, but not the second. Aside from Japan and Hong Kong, East Asians don't live longer on average than people from Europe. Furthermore, most Asian-Americans are of Chinese, Korean, and Filipino heritage, who globally tend to have lower life expectancies than Europeans. So really the situation of Asian-Americans living longer than European-Americans is actually the opposite of the situation globally -- which depicts Europeans living longer than most East Asians.

I am going to delete the second part of the sentence because it doesn't fall in line with the evidence. — Preceding unsigned comment added by TheyCallMeTheEditor (talk • contribs) 00:22, 8 August 2012 (UTC)

Okinawans
I took away the section on Okinawans. Seems little more than conjectures... Thoughts, anybody?

Paolo (talk) 13:21, 1 May 2009 (UTC)


 * I restored the section that was referenced. The second section was total conjecture and needed to go, but the first section is true and should stay until proven otherwise. --ErgoSum88 (talk) 22:47, 1 May 2009 (UTC)


 * Even if true, it's just a factoid which really adds nothing meaningful to the article. We could find out which city with a population of under one million has the greatest proportion of people over 62, but what is the scientific significance of that? Nothing. -- Paul Richter (talk) 09:50, 11 May 2009 (UTC)

Average life span
"Average life span" or "average lifespan" could be better defined in this article because it does not appear anywhere else on the wiki. Snowman (talk) 18:08, 29 June 2009 (UTC)

Removing Facts
Someone removed the fact that the seriously mentally ill die 25 years sooner. I made a graphic and included references. Why did these facts get erased?--Mark v1.0 (talk) 11:17, 27 July 2009 (UTC)


 * update: I put seriously mentally ill back in.--Mark v1.0 (talk) 13:04, 27 July 2009 (UTC)

Again, I can not find seriously mentally ill average life expectancy.--Mark v1.0 (talk) 22:09, 15 June 2011 (UTC)

It's pretty easy to find documentation that documents persons who are seriously mentally ill or seriously physically handicapped have a shortened average lifespan .... but that can be said about many conditions. So what? WHY is this category so qualitatively different or substantially related to the concept of life expectancy that it warrants special notice when other genetic and acquired medical illness do not? That section should be removed in my opinion. I would be happy to post the underlying citations in an appropriate location in Wikipedia, just not here. — Preceding unsigned comment added by 71.235.36.31 (talk) 18:12, 16 August 2011 (UTC)

I have not seen any response to my request for a justification for inclusion of "seriously mental illness" ass a category warranting special inclusion in the life expectancy topic when the rest of human diseases are not categorically considered. (Clearly a complete listing of the scope of disease particulars affecting life expectancy would fill several books, hence my removal at this point.) Just because something is a "fact" does not make an especially relevant fact. — Preceding unsigned comment added by 71.235.36.31 (talk) 05:30, 7 September 2011 (UTC)

I see no effort to justify inclusion of a Serious Mental Illness section so after waiting 2 years I am again deleting it (after removing a misdirected link). The remaining link is also of low quality. Surely there is a mental illness topic area where this knowledge might be cited, and surely there are better citations to many studies in the medical literature indexed in PubMed or one of the medicla journals. — Preceding unsigned comment added by 2601:9:D80:47F:A916:B506:4125:C86D (talk) 20:45, 10 October 2013 (UTC)

Bronze Age
There is a claim that the average life expectancy in the Bronze Age was 18 years, and another claim that it was 40 to 60 in Sweden during the same period. They are both cited. The first claim is cited to a material that is clearly not academic, and the second one is a web site in Swedish; sources for English pages should be in English. I believe both claims should be removed, or their citations replaced with credible and English sources. Cliobella (talk) 10:18, 13 August 2009 (UTC)

Infant/child mortality rate in London, 1700s and 1800s. Correct?
Both this article and World_population include the statement: "The percentage of the children born in London who died before the age of five decreased from 74.5% in 1730-1749 to 31.8% in 1810-1829."

Is this taken out of context? Was there something specific going on in 1730-1749 that caused this? If so, that should be noted. It's extremely hard to believe that nearly 3 out of 4 children in London died before the age of 5 in 1730-1749.

Maybe the actual case is something like, "of children who died, 74.5% of them died before the age of five"?

Even if the numbers are correct, it's certainly not representative of what was going on worldwide before Industrial Revolution. If 74.5% of children were dying before age of 5, each woman would need to be having something like 9-10 children total just to have a stable population.

Reference is an old book, so not easy to check what the original context was. --68.142.54.95 (talk) 03:34, 17 September 2009 (UTC)

Popular misconception
I was wondering if there were any reliable sources on the popular misconception where Life expectancy is equated with how old people got. I remember seeing it presented that way in 1960s history books; it was also presented that way at the end of the In Search of... episode "The Man Who Would Not Die" (About Count of St. Germain) where it is stated "Evidence recently discovered in the British Museum indicates that St. Germain may have well been the long lost third son of Rákóczi born in Transylvania in 1694.  If he died in Germany in 1784, he lived 90 years.  The average life expectancy in the 18th century was 35 years.  Fifty was a ripe old age.  Ninety... was forever."--BruceGrubb (talk) 07:31, 29 November 2009 (UTC)


 * Yes, it is a bit misleading because the life expectancy of 35 years was influenced by a high rate of infant mortality. The modal age at death would have been well over 50. See http://www.york.ac.uk/depts/maths/histstat/halley.pdf - this suggests that the modal age at death was somewhere between 60 and 70, and it would be more meaningful to compare this individual's age of 90 with the latter. -Ehrenkater (talk) 16:39, 29 November 2009 (UTC)


 * Thanks for the link though I am still wondering if any reliable sources flat out address this misconception of life expectancy being how old people got.--BruceGrubb (talk) 12:46, 30 November 2009 (UTC)
 * What exactly do you mean by "how old people got"? -Ehrenkater (talk) 17:39, 30 November 2009 (UTC)


 * Exactly that. Per the In Search of example above it is implied that few people lived past 50 because the average life expectancy was only 35 but as you noted a high infant mortality would bring this average down.  In terms of population pyramids if the 18th century was a type 1 or type 2 expanding graph would radically alter how long you were expected to live past childhood.--BruceGrubb (talk) 15:59, 3 December 2009 (UTC)


 * This has been bugging me forever. I've read people claim that in Ancient Greece, nobody became older than 25. *rolleyes* Even Ötzi was 40, and he didn't even die of a natural cause! Even in the most primitive societies and the poorest third-world countries, there are plenty of old people. If no-one became older than 25, how could families and worse still, cultural traditions even exist? In Europe in not so remote times, people only started to get children at 30! Any society with such a short lifespan would have died out as there would have been no time to raise children and teach them the community language and the traditions of one's culture. Old people were very important in all pre-modern cultures, in fact. Sometimes I wonder if there is a vested interest in portraying pre-modern societies in such grotesquely distorted ways. Just imagine if it turned out that progress since medieval or ancient times didn't bring such huge improvements for life expectancy (and in consequence, quality of life) as lists such as Life expectancy suggest (and this is even a relatively good list, despite the fact that life expectancy at birth is misleading; usually, you simply get diagrams with a slowly rising and eventually quickly soaring curve, anomalies such as Bronze Age Sweden or variation between local cultures totally censored out). Florian Blaschke (talk) 22:57, 2 January 2010 (UTC)


 * Until recently, the majority of the increase in life expectancy was accounted for by reductions in infant mortality. According to Psalm 90, a typical age at death in ancient times was 70 (threescore years and ten). Claims that a typical age at death was 25 are simply false. Ehrenkater (talk) 22:48, 3 January 2010 (UTC)

John Adams Sr hold the title "oldest US president ever" since 1803 when he surpassed George Washington until 2001 when Ronald Reagan surpassed him, but Reagan only elected president relative late age, despite the fact during period life expectancy at birth in US almost doubled Median age at death of eight earliest US presidents was about 80 yearsCristiano Toàn (talk) 10:45, 16 January 2012 (UTC)

Historical life expectancies
Just a note on the table comparing the life expectancy of different historical epochs: The Upper Paleolithic entry seems to get it's "54 at age 15" number from the Kaplan et al 2000 article. Specifically, from Table 1, page 158, the "forager mean" of 54.1. In my mind, there is a problem with this: Kaplan et al's study surveys the data from modern foraging groups, and does not deal with the fossil record. Whether the life-histories of modern foragers is indicative of life in the upper-paleolithic is an often-questioned assumption. The second study quoted, by Caspari and Lee, while very interesting, does not actually comment on life expectancy, but rather on ratios of old-to-young among the Pleistocene fossil record. These may not be the best sources for the data point in question; though to be honest, I don't have an idea concerning what could be used instead. — Preceding unsigned comment added by 76.226.143.133 (talk) 05:05, 15 October 2011 (UTC)

There are many thousands of biographical articles on wikipedia alone which attest to people in earlier centuries having attained the ages of 70 or 80 years, which is very comaparable with modern life expectancy. It is seems pointless to request further citations of this obvious fact. -Ehrenkater (talk) 00:06, 18 March 2010 (UTC)
 * I've removed it per WP:PROVEIT, as I indicated in my previous edit-summary.
 * I think WP:MEDRS should be applied as well. --Ronz (talk) 01:46, 18 March 2010 (UTC)
 * This is the flip side of the misunderstanding point I raised above. It is perhaps clearer if I link some actual life expectancy graphs (also called life tables or Period Life Expectancy tables):


 * National Vital Statistics Report, Deaths: Final Data for 1998


 * Period Life Expectancy, SSA


 * [http: //www.annuityadvantage.com/lifeexpectancy.htm Period Life Expectancy, SSA November 10, 2008]


 * Plymouth Plantation; "Dead at Forty"


 * Life Expectancy by Age, 1850–2004


 * The problem is most statements about historic life expectancies use the at birth calculation based on very fragmentary data. You will notice in the 1850–2004 chart there is a major jump between at birth and at age of 20 until about the 1950s.  That a person who lived to 21 in the Plymouth Colony had a expected life of 69.2 and they actually live that long their expectancy became 79.9 show the problem.   While I was doing some searching I found this which might help:


 * Jonker, M. A. (2003) Estimation of Life Expectancy in the Middle Ages Journal of the Royal Statistical Society. Series A (Statistics in Society), Vol. 166, No. 1, pp. 105-117--BruceGrubb (talk) 15:43, 17 May 2010 (UTC)


 * I get the concept, however, I agree with the OP - the original source does not adequately support the modern forager being equivalent to an ancient forager. The comparison may hold up, but as it stands it's just a hypothesis and doesn't belong in an encyclopedia imo. 110.174.212.132 (talk) 13:22, 25 September 2013 (UTC)

Norway in the wrong color
The average life expectancy in Norway is 80.85 after new numbers. Source: http://www.ssb.no/english/subjects/02/02/10/dode_en/ —Preceding unsigned comment added by 98.201.123.174 (talk) 18:21, 20 May 2010 (UTC)

Military service in Imperial Rome as a guideline
The military reforms of August fixed the following times of service : 12-16 years for Praetorians, 16-20 for plebeians (legionaries), 25 for auxilliaries. I fail to see how one can hope to reconcile these figures with a life expectancy of 28 years! 81.80.129.154 (talk) 14:06, 21 May 2010 (UTC)


 * It's very easy when you realize that the 28 years number is an average that includes a high child mortality rate.  Say you have two people born the same day but one dies at the age of 2 but the other lives to the age of 80; the average age of those two people is 41 ((80+2)/2) and if you averaged three people of 2, 3, and 80 you would get an average age of only 29!  As you can see it doesn't take that many child deaths to send the average down and this is exactly what the chart in [Roman Life Expectancy] shows.  Just living to the age of 5 nearly doubled your life Expectancy from 25 to 48.


 * Remember that in the time of the Second Punic War (218-201 BC) iuniores (property-owning Roman citizens) between the ages of 16 and 46 could join. Augustus decided in 5 CE that instead of having soldiers settle in colonies or other places that they would be given a lump sum equivalent to twelve years' pay; this turned out to be so disastrous to the treasury that Augustus lengthened the term of service in 6 CE.  Even with the rigors of warfare a sizable part of the Roman army was able to survive their tour of duty.--BruceGrubb (talk) 18:39, 24 May 2010 (UTC)

as indicated in some other places on this discussion page, there is a common misconception of what life expectancy is. it would be much better, IMO, to differentiate life expectancy at birth and at some age of maturity, say 18. leaving this article as is does not only confuse many, it leaves wrong impression of average age at death, which is what most people think about when talking about life expectancy. just personal opinion.

Forecasting human mortality
I am interested in editing this page to include a section on mortality forecasting, as well as starting a page on the Lee Carter method in human mortality forecasting, a problem of great import for social security and other programs that support an aging population. It is a big enough topic that I probably can't knock out a full blown section in one sitting, so if my attempt seems incomplete, I hope all concerned will be patient.

Does anyone object or have any thoughts?

I would like to be forthright and mention that I am a developer for a free / open source online mortality forecasting tool which I would like to link to in addition to the other libraries that are out there. I would put the link here in the talk page, but it seems like spam unless I have the other links to accompany it, and I don't have them at hand.

Here is my working section: User:Forkandwait/mortality_forecasting. Feel free to browse and comment. If I don't hear any complaints in the day or so, I will copy my text to this article.

Forkandwait (talk) 21:51, 6 August 2010 (UTC)

Life expectancy "index"?
I think this section should be deleted. Life expectancy might be considered an index of the collective healthiness of a country, but it is generally reported just as "life expectancy". There is no index *of* life expectancy, at least that I know of; such an index would be what "life expectancy index" would refer to.

This section could be re-titled "Uses of life expectancy as an index of health", and then reworked, if someone wants to do that. I don't think it is worth it.

If I don't hear any objection in the next little while, I will delete this.

Forkandwait (talk) 05:13, 8 August 2010 (UTC)


 * This UNDP Technical Report reveals it's simply life expectancy at birth scaled to range from 0 to 1 (see box p356) as an intermediate step to calculating their human development index. I agree this isn't worth a separate section, and present this section is just confusing. On the other hand perhaps it's worth having a link to human development index somewhere on the page in a sentence to just say life expectancy is one of 3 components used in its calculation. Qwfp (talk) 08:27, 8 August 2010 (UTC)


 * What do you think of a "Uses of life expectancy" section? Then we could put this in there.  Perhaps a "uses and abuses" -- then talk about the misinterpretation based on high infant mortality? (that should be a separate section probably) Forkandwait (talk) 17:14, 8 August 2010 (UTC)


 * I added a "Life expectancy vs. life span" section to partly address this problem. Based on the source I found the problem seems to be due to a layman misinterpretation of "life expectancy" meaning "life span" because they don't fully understand the former is an average.  My problem has been finding reliable sources that document the issue.--BruceGrubb (talk) 01:11, 2 October 2010 (UTC)

Disability
"In the Western world, people with a serious mental illness die on average 25 years earlier than the rest of the population[citation needed], even though there is no objective test for mental illness[citation needed]. Mental illnesses include schizophrenia, bipolar disorder and major depression. Three out of five mentally ill die from mostly treatable diseases, such as Heart/Cardiovascular disease, Diabetes, Dyslipidaemia, Respiratory ailments, Pneumonia, and Influenza.[citation needed]"

I would suggest deletion of the uncited references, because at present they detract from the article. The "citation needed" tags have been there for some time and nobody has provided references.Jimjamjak (talk) 11:23, 22 January 2011 (UTC)


 * I've removed this section for the moment. It is possible that a short section referencing the indirect influence disabilities have on life expectancy could be included, but much of the relevant information is better covered in QALY and disability-specific articles. Perhaps a few more inter-wiki links?Interrapax (talk) 03:00, 16 May 2011 (UTC)

Problem with Table in Section 2.1
"Life expectancy variation over time - Differences in life expectancies from the 20th to 21st Centuries in 30 Countries are displayed below."

Actually there are no countries listed, so the table doesn't make any sense - it's just two columns of figures, one headed 1900s, the other headed 2000s. Has a column with a list of countries been accidentally deleted or something? Muzilon (talk) 09:20, 21 September 2011 (UTC)

Life expectancy for people who make it past five years old
Are there any sources of data we can add that give tables of historical rates for those who make it past five years old? That is, removing the skewing effect that infant mortality has on 'average' age of death. I have been looking at UN and WHO sources and found none. Any leads appreciated. Thanks. Span (talk) 12:45, 5 November 2011 (UTC)
 * What you are looking for is either e5 (life expectancy at age 5) or e5+5 (average age at death of those surviving at age 5). If
 * U5MR = under-five mortality rate
 * e0 = life expectance at birth
 * e5 = life expectance at age 5
 * a = average age at death for those dying before age 5 (typically a little less than 2.5 years; e.g. 2,48)
 * then e0 = a*U5MR + (1-U5MR)*(5+e5)
 * or e5 = [e0 - 5 + (5-a)*U5MR] / (1-U5MR}
 * or e5 +5 = [e0 -a*U5MR] / (1-U5MR}. Touchatou (talk) 13:45, 16 January 2012 (UTC)

128 year old person?!?
Just reading this article: "The oldest confirmed recorded age for any human is 128 years (see Aend Ethiopia)." This is highly unlikely. Jean Calment is generally accepted as being the oldest at 122 years old. Googling the name shows a Youtube video of a man who claims to be 128 but this is almost certainly incorrect. Has this been added to the article due to vandalism or is someone simply that gullible?!? 87.112.102.24 (talk) 15:10, 29 August 2012 (UTC)

Math problems with "Calculating Life Expectancies" section
This section may be in need of an edit from an expert with a sound knowledge of probabilities and the math involved in calculating life expectancies. I claim to have no expertise in this specific area, however, I deal with mathematics and probability at a high level as a university instructor and researcher and the equations presented seem to me to have some logical errors. For starters, the start index in the summation presented as the calculation of life expectancy at age x changes from one side of the equals sign to the other, and for no discernable reason since when t=0, then the contribution on the right hand side is also 0. Also, if the left and right hand sides of the equation were truly equal, then this would imply that t*q_(x+t) always equals 1, which implies that q_(x+t) always equals 1/t. This would be an absurd conclusion. It also does not make sense to me to simply sum all the p_x's to get e_x. This does not seem logical. The right hand side, however, does seem logical, as it seems to be summing over all t, t multiplied by the probability of surviving exactly t years after age x (which we get from multiplying the probability of surviving t years, multiplied by the probability of dying in the next year, GIVEN that one has survived those t years). In essence, the right hand side of the equation I can believe, and seems logical, but the left hand side seems to me to be in error.

Is there anyone with more expertise who can shed some light on this? Is my reasoning in error in some way, or is the equation truly incorrect as I am suspecting? — Preceding unsigned comment added by78.100.89.89 (talk) 09:11, 15 March 2013 (UTC)


 * Agree that this is confusing. The paragraph is not clear - it should be stated that the expectation is a conditional expectation of future lifetime, given survival of the life to age x. If K(x) is the curtate (whole years) future lifetime random variable for (x), then the expected future lifetime is the expected value of K(x) given survival to age x, and denoted ex.


 * $$e_x := E[K(x)] = \sum_{k=1}^\infty k P(K(x) = k) = \sum_{k=0}^\infty k {}_k p_x ( {}_1 q_{x+k})= \sum_{k=0}^\infty k {}_k p_x \, q_{x+k}.$$


 * Here $${}_t q_{x+k}$$ denotes the probability that a life age x+k dies within time t. The left subscript t is omitted when t=1.


 * This part of the equation from the article was correct
 * $$e_x = \sum_{t=0}^{\infty}t \,_tp_x q_{x+t},$$
 * but we typically use index k rather than t in this context. Mathstat (talk) 23:01, 15 March 2013 (UTC)


 * For an explanation of the other part of the formula, see the revision in the article.Mathstat (talk) 23:53, 15 March 2013 (UTC)

Mention the Bible?
Psalm 90 in the Hebrew Bible is famous for saying "The days of our years are threescore years and ten" (KJV). Is that worth mentioning in the "Life expectancy variation over time" section? Scholars would date Psalm 90 anywhere from 1500 BC to 500 BC, but regardless, the estimate has a very modern-sounding ring to it, and I suppose it demonstrates that in particular cultures there may be a much higher expectancy. I'm sure we could find some good secondary sources, such as. StAnselm (talk) 07:34, 12 April 2013 (UTC)

unequal power relations
amazing, how there is little to nothing on the impact of income inequalities on life expectancy or even the relationship between imperialism/colonialism and the fall in life expectancy in countries like Africa, Latin America, and Asia. So many educated folks on wikipedia, so little critical minds... — Preceding unsigned comment added by Ditc (talk • contribs) 06:06, 31 August 2013 (UTC)
 * I do believe you just added yourself to that list. Nonetheless, to make your comment productive perhaps you have some freely accessible reliable sources you could post on the talk page for people to use if they're so inclined. --Rhododendrites (talk) 13:16, 31 August 2013 (UTC)

Calculate life expectancy section re-written and re-organized
To all who may concern,

The "calculate" section has been re-written and re-organized by me.

The original text were very un-organized, in that it copies a lot of formulas from other sources without explaining the major ideas and steps behind the mathematics.

The principle is to explain things as simple, as straightforward, yet as informative as possible. I believe by the current rewriting, it improves towards that direction. Further improvements based on this version by the community are greatly welcomed. — Preceding unsigned comment added by 147.8.183.93 (talk) 07:54, 22 November 2013 (UTC)
 * I've restored the referenced prose, which was replaced by unreferenced equations. If the goal is simplification, then please edit and clarify the prose, and please don't delete the references. Thanks, Ruby   Murray  09:17, 22 November 2013 (UTC)

I have restored it again. The texts there simply do not give readers the key ideas and physical meanings of the mathematics of life expectancy. They are just terribly written based on un-organized materials. --Puekai (talk) 12:36, 22 November 2013 (UTC)
 * Please stop deleting references which are used elsewhere in the article. If the prose is badly written, then please correct it. Please also have a read of Edit warring, and get consensus with your fellow editors before reverting it again. Thanks. Ruby   Murray  12:43, 22 November 2013 (UTC)