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Nature of Errors in the Construction Documents

Abstract To minimize errors you have first to know it, as once an error has been identified it is possible to take action to address it. This research represents some important fact about errors in the construction documents. This research have defined errors, discussed and identified many types of errors in the construction documents through thoroughly investigation of 30 case study projects. The errors in construction documents can be classified to Failure to conform to design parameters, Coordination problems, Failure to address operability and constructability issues, Failure to follow procedures, Omissions, and Erroneous actions The observation give an indication that minimizing the amount of errors generated during the process of developing the construction documents is achievable and applicable as erroneous and missing items type of errors are the most type of errors occurred in the construction documents.

Keyword Design activity; design practice; design problems; drawings; Documents quality; Errors types

Introduction The incidence of errors in construction design and contract documentation is a major factor in poor project performance. Whilst previous investigations have been carried out to identify and classify the types of errors that lead to time and cost overruns in projects, little empirical work has gone beyond a taxonomy/classification of errors. The work presented in this paper builds on existing knowledge of construction document errors through a detailed empirical study on a sample of projects in Saudi Arabia. Following a pilot study, 30 case studies of completed projects were thoroughly reviewed to identify, classify and enumerate the errors which occurred, through detailed document review and data collection from associated consultants. The objective is to create an ‘error profile’ of projects, which quantifies the type and frequency of errors that can occur in projects. Such an approach should allow a better understanding of where most errors occur in projects, in order that more attention can be directed to areas having greatest impact on the project. Ultimately the aim is to address the source of errors to reduce their number and lead to better project performance. To minimize errors you have first to know it, as once an error has been identified it is possible to take action to address it. This work is part of an ongoing study to investigate the source as well as occurrence of errors.

1	The problem The early control of the project during the design stage is no doubt very important. The most effective benefits are gained at the beginning of the project, in establishing scope and levels of quality, making schedule decisions, selecting delivery options, and translating requirements into design concepts. The project’s big decisions are made up front, and these lay the groundwork for all the decisions that follow. Many researchers indicate that the consultants play a major role in project cost overrun, due to the lack of the adequate information by them (Rukn, 1999), Errors in contract documents (Love, et al 2000, Kirby 83) and Quality of contract documents (Stasiowski, et el 94). This is has been supported also by the investigation of the frequency and severity of claims on federally funded and administrated projects which found that design errors were the single most common cause of contract claims, accounting for 46% of the additive claims that were reviewed (Diekmann and Nelson, 1985). The most pernicious cases of lost time and cost in construction project are due to errors and omission in the construction documents. Many of these errors, unwanted by any of the design team, unforseen but not unavoidable, could through site work into disarray Elimination of errors in construction documents plays a major role in controlling the objectives of the project. A study (Kirby 1983, Morgren 1986) found that 56% of all contract modifications are to correct design deficiencies. In UK Hibberd identified the major source of variations on the construction works are inadequate consideration of design (25%), design initiated (19%), and defect in contract documents (16%) (Hibberd 1980). Also in UK Langford et al. research showed that 72% of variations caused by the design team (Langford et al. -1986). Thus, controlling errors during the pre-contract stages while preparing the construction documents is crucial for the improvement of the construction industry.

2	Scope of the research Even though the finding of current research might be applicable every where in the construction industry, the research scope has been limited to Saudi Arabia as the collection of data and case studies has been extracted from Saudi Arabia Construction projects. For the purpose of the present research the definition of the construction documents has been identified as the written and graphical documentations which communicate in professional matter and compliance with regulations and laws for the tendering purpose all needs, wants, and knowledge of the project stake holder to contractor(s) for the purpose of construction the project and which enable the client and/or designer a smooth and effective administration during the construction stage within the set objectives of time, cost, and quality Despite the fact that the construction documents are a continuation of the early stages of the design, for the purpose of this research, only errors in documents which have been handed to contractor for the purpose of bidding or construction will be considered, as it is very difficult to trace errors which are considered a normal procedure of developing the project between the designer and the Client.

4	Definition of errors Error in construction documents has been defined as a non-desired condition and the non-fulfillment of intended requirements in the construction documents which will have influence on time, cost, and quality of the project. The changes, which are made because of new or changes of requirements during documents production stages are beyond the scope of this research. During preparation of this research it has been found that many errors are known to practitioners and many different types of errors have been listed by different literatures (Stasiowski, et el 94) specially in Quality Assurance (QA) and Control (QC) review, without explaining the extent of their occurrence - considering errors as an acceptable facts in documents - and without discussing the possibility of eliminating / reducing incident of errors in the construction documents?. For purpose of preventing repetition these errors will be combined with a coming section. In addition, the literatures did not give any indication about the spread of different types of errors in the construction documents and there was no attempt to classify these types of errors as per their original cause so they can be eliminated.

5	Research Methodology In order to increase the validity of the research data, it was decided to collect data from case study projects. The case study places more emphasis on the full analysis of a limited number of events or conditions and their interrelations. A pilot study was conducted with the detailed study of five projects ( refer to table-1) where a detailed analysis of the documents has taken place including drawing by drawing review for all discipline of the project and the review of the supported documents of tendering queries and variation orders to obtain a detailed idea about errors which are occurring in the construction documents. All types of errors which have been marked on the drawings and documents and have been accepted by the design team for the purpose of revision were recorded, listed and counted. To find the spread of these types of errors in the construction documents a list of errors found in the pilot study together with the type of errors collected from literature review has been prepared and distributed to professionals to add any types of errors which they have encountered during the production of the documents ( refer to table-2). Due to the scale of detail required to get the information needed from the case studies which imposed limits on the number of projects that could be included in the study together with the benefit of experience gained from the pilot study it was decided to limit the sample of the case study to those projects where: -	there are records of quality control set, bidder queries, and/or final project variations list, -	availability of some members of the design team. Based on the above rule 30 case study projects have been studied to find the distributions of errors in the construction documents of Saudi Arabia. The list has been discussed with members’ of project design of the case study project to see the spread of type and amount of errors in his project. Even though the case study project have been selected basically on pragmatic bases i.e., their availability, however, they represent diverse types of project as shown in table 3 and 4. 6	Types of errors in construction documents The influence of errors in design documents is large as Koskela (1992,p35) suggests that it "sometimes seems that the wastes caused by design are larger that the cost of the design itself". Some of the errors mentioned here have been listed only in other literature with no further explanation (Stasiowski, et. al. 1994). In this research we have traced different types of errors encountered in the Q.A. process with explanation, discussion the influence of their occurrence, their nature and frequency. Also, this research studied the extent of error occurrence in different types of documents, i.e. tender documents and variation orders as well as Q.A. Documentation; as the spread of errors are different between documents. The review of the case study projects in conjunction with literature have identified the following types of errors, which are occurring in the construction documents:

6.1	Erroneous The most serious category where human make mistakes and wrong decision and at the same time the highest percentage of occurrence as the research found that 30 % of all errors were falling within this category. The highest percentage of this error were among the private sector client (54%), then government client as the 11% and the least were within the developer as 11%. This may indicate that the developer generally know their requirements which reduce the occurrence of this type of errors. For procurement the design and build was the lowest (20%) and construction management as the highest (41%) which may be due to that construction management normally start while all the documents are not complete. The following are the main types of errors which occur under this category: 6.1.1	Errors in capital cost estimating Many companies realize that budget overruns are not necessarily the result of bad project control/cost control work, but are rather the result of bad capital cost estimating and budgeting work. Evidently many unfortunate budget ad control estimates could have been drastically improved if some simple and well-known facts had been implemented. (Sigurdsen 1996). The research found that 4% of all errors were this type of errors. This type of errors is discovered during the tendering stage, when the bidders submit their offer to execute the work. The designer may have to do the exercise of reducing the cost of the project or revise the documents to stay within the client budget if he had signed a contract of guaranteed maximum cost. In this case the error will delay the start up of the execution of the project. The error is serious in some situation as it might lead to the cancellation of the project, if the estimate is beyond the capacity of the client. 6.1.2	Designer errors These types of errors are the most serious. It is related to the pure mistakes of the designer due to the lack of education, knowledge or experience. These errors include missing item(s) in the design, missing consideration of some important item in the design. The research found that 6% of all errors were this type of errors. These errors may cause the failure of the documents to deliver the purpose of the project. In one case study project the failure of the designer to consider the appropriate height of the mezzanine floor caused to discard the use of that floor as rentable space and it has been used as a store area only. This type of errors leads to loses of client due to rising of claims for request of time extension and compensation of costs due to extra time required to correct the errors and revise the documents accordingly. 6.1.3	Error in project contextual factors As the standard procedure, there is always a geotechnical survey and site visit before starting the design of the project, but it has been found that some errors occur in the construction documents which ignore some important factors which are critical in the design of the project, such as soil characteristics, site contours, and the access to the site. Arics (Arics, 1987) found that contextual differences such as limited working areas or whether have been found to significantly influence construction costs. The research found that 3% of all errors were this type of errors. This type of error is mainly the result of missing or misleading information regarding the project site. It will lead to delay of the start up of the project and compensation for the contractor to correct the documents as per the site condition(s) and requirement. 6.1.4	Errors and omission in the bills of quantities Researchers identified errors and omissions in the bills of quantities as a main source of variations in the construction projects (Choy & Sidwell -1991). The practice of pricing the project in most contract procurement is dependant on the bills of quantities. However, the influence of this type of errors on the project depends on the procurement of the contract selected for the execution of the project. When the contract is based on lump sum price, this type of errors may raise many queries during the tendering stage and will lead to bad impression about the designer firm. During the construction stage when an item in the bills contradict other documents it might lead to claim for cost compensation and request for time extension. The research found that 5% of all errors were this type of errors. The types of errors found under this heading were: -	description of items are wrong -	the item is missing in the bills of quantities -	the measurement is wrong -	the item is included in the bills but not shown in the drawings -	the unit of measurement is wrong

6.1.5	Errors in Specification The specifications present written requirements for materials, equipment, and construction system as well as standard for products, workmanship, and the construction services required to produce the work (AIA, 1994). The research found that 4% of all errors were this type of errors. Errors include missing items in the specification, items included in the drawings but in the specification or vice versa, items do not conform to client / discipline criteria, list of applicable applications incorrect, or inconsistence with industry practice. This type of errors when discovered during the construction stage will raise claims for either cost or time extension or both of them. 6.2	Missing or incorrect items The research found that 22% of all errors were falling within this category of errors as the second highest category. As the previous category, the types of errors which fall within this category could be reduced to improve the construction industry if proper system is in place. The research indicates that this class of errors occur mostly within private sectors projects (57%) and the least within the developer (9%) and 33% within the governmental project. For procurement type the most occurrence were among the traditional 44%) and the least with the use of design and build (21%) and 35% with the use of construction management. The following are the main types of errors which fall within this category: 6.2.1	Callouts incorrect or missing The callouts - which describe different aspect in the drawings or details, either wrong or missed or do not describe clearly what is meant by the callout. The common error within this categories is the "vague statement" such as; Thermal insulation, Natural stone: - such statement does not describe the type, size, or method of fixing. The research found that 8% of all errors were this type of errors as the third highest types of errors occurring while preparing the documents. This type of errors has impact on the understanding of the project and interpretation of the documents for the purpose of pricing and construction. It might lead to change variation orders as the contractor might price for item as per his understanding, not per what is meant by the designer or required for the project. 6.2.2	Incorrect or missing notes The notes are the text on the drawings which convey the intent clearly, describe the contents or set up the conditions for the applicability of the design in the drawings (AIA, 1994). This category of error includes: the note is not applicable to the drawings or details, describes wrongly what it is meant to be, or additional note is needed to make the drawings clear and understandable. The research found that 6% of all errors were this type of errors, which might raise claims for extension of time if notes are missing or the content of the documents are vague. It might also raise request for time extension and cost compensation in the case when the note is incorrect. 6.2.3	Additional views / details needed The research found that 9% of all errors were this type of errors as the highest type of errors that take place in the process of developing the construction documents. The documents as they are do not convey the information clearly to the contractors. The documents need more details to be clear and understandable because of the ambiguities in the current state of the documents. This type of errors might raise many queries during the tender stage or claims for extension of time during the construction stage if detail(s) are missing or the design is not clear.

6.3	Nonconformance to purpose of construction documents 16% of all types of errors are falling within this category where documents do not conform with the purpose of producing the documents. The highest occurrences of this class of error were among private sector project (52%) then governmental project (35%) and the least within the developer projects (13%). The lowest occurrences of these errors were with the use of traditional procurement (24%) then design and build (28%) and the highest were with the use of construction management (48%). The following are the main types of errors which are under this category: 6.3.1	Document does not conform to client’s design criteria The client normally sets the scope, quality, and budget. The prospective project is defined at least well enough to understand what it is being undertaken, what facilities and amenities are required, when the project is needed, and how much it is likely to cost. (AIA, 1994, p377) Failure of the design team to address any requirement or constraints set up by the client in the construction document is considered as an error. Love (Love, et. al., 1999) found that errors in the design stages of the project are the result of the lack of understanding and incorrect interpretation of customer requirements. The research found that 3% of all types of errors were this type of errors. As we have defined the construction documents, this is a violation of the purpose of the construction documents. Contractually, the designer has to develop a design solution based on the approved project requirements and constraints. The client has the right to pursue the designer to correct the error if it has been proved that the construction documents failed to address the requirement of the client brief. Failure to address the requirement of the client at the early stage of the documents development process will raise the cost of change at later stage, as we have discussed earlier. The impact of this type of errors is enormous to the client, as the project does not satisfy his full requirements and this might raise the cost of the project due to variation change and delay the delivery of the project on time, for the designer, it might be a ground for legal case against him and he has to bear the cost of revising the construction documents. 6.3.2	Document does not conform to code The primary regulatory instrument for the design of buildings and structures is the building code. It also provides fundamental design parameters as well as for a great many design and construction details (AIA, 1994-p663). Compliance with building code generally is duty that cannot be delegated, and code violations in construction documents may be considered evidence of negligence on the designer's part. Often, it is not sufficient that the designer has complied with the local custom or practice if such conformant start. The research found that 3% of all types of errors were this type of errors. Failure to conform with the code at the beginning of the project will result in design change later and will delay the project. This type of errors might be discovered during the authority approval of the document, if it is not, then the final check up of the project after the construction will discover it. If it is not discovered then during the occupation of the project, violation of building codes can cause injury to building users and expose designer to legal liability and possible revocation of their licenses (AIA, 1994, p377). If it is discovered during the construction stage then the delay and cost of change will be enormous for the client, who may purse the designer to pay the damages. The seriousness of this type of errors is that neither an owner's requirement to disobey the code not a building officials' unknowing or unreasonable approval of a noncompliant project relieves the designer of this duty. 6.3.3	Document does not conform to design calculations Every discipline is based on some standards which are used to calculate different needs and requirements. Failure to conform to these calculations will result in violation of the codes, and failure of the system used for that discipline. Many clients request the calculation to be part of the construction documents, so he can check the assumption of the designer for the used system. The main cause of this type of error is usually lack of experience from the designer, or carelessness or pressure of the time. The research found that 3% of all types of errors were this type of errors. The difficulty of this type of errors that it is not easy to discover during the process of the producing the construction documents. It might be discovered if it is too obvious error, or the design do not make sense. If the error is discovered during the construction stage it will raise the contractor's change variation orders and he will claim for extension of time and compensation for the extra costs. The client will purse the designer at their expenses to correct the error. 6.3.4	Document does not conform to vendor data Also, this type of errors was a factor in the development of many strategies in the construction industry, such as Partnering, Concurrent engineering, etc. where supplier(s) participate in the process of developing the construction documents. Every vendor got his own equipment, specification, and material and requirements for his product to work probably or to get the best performance. The errors may lay in the incompatibility of equipment, out of date specification, and inappropriate materials. The research found that 4% of all types of errors were this type of errors, as the highest within this category. This type of errors will cause delay in the project and will increase the cost of the project due to raise of change variation orders. Client has to approve vendors at very early stage of the design. The early involvement of the vendors in the process of the construction documents can help the designer to minimize such errors. 6.3.5	Incompatibilities of documents with building regulations Projects respond to many regulations and other design parameters. Communities establish rules for development to protect public welfare and conserve environmental resources. Building regulations create important disciplines for the designer. It is imperative that designers design in compliance with regulations unless they obtain variances or specific ruling allowing alternative solutions (AIA, 1994, p653). Regulations include: Zoning requirements, Planning regulations, and Environmental regulations. NEDO (NEDO 1988, p76-77) has identified incompatibilities in design and design details with building regulations as a source of errors in construction documents. The research found that 2% of all errors were this type of errors. Failure of designer to conform to the regulations will lead to delays in project until the approvals are obtained and may raise cost of the project due to change order which the client has to pay for, if discovered during the construction stage. 6.3.6	Document does not confirm to the law The research found that 2% of all of errors were this type of errors, as the lowest rate within this categories. These types of errors are those which does not confirm to the law used for certain types of project and clients e.g. the law has stated in Saudi Arabia (and many other countries) that any government project should specify local materials and supplier (if available), such errors when discovered during the construction stages will cause a delay in the project and may raise cost to the client due to increase in price of the local materials..

6.4	Errors due to the process of preparing the construction documents The research found that 15% of all errors were falling within this category. If there are system in place and have been followed, this category of errors can be eliminated or at least reduced to minimal occurrence. The least occurrence of error of this type was with the developer project client (11%) while the maximum occurrence was with private client (23%) and it was 34% with government client. Whilst the most occurrences were with construction management procurement (43%) and the least with design and build (22%) and it was 35% with traditional procurement. The following are the main types of errors which fall under this category: 6.4.1	Document does not conform to drafting standards To facilitate the production of construction documents and to build consistency between drawings and from project to project, and to make it easy for other people to read and understand the drawings probably most offices employ documentation standards (AIA, 1994). These standards may address subject as: -	Drawing sheet sizes, layout, scale, sequence, numbering -	Line thickness, and lettering sizes -	References within the documents -	Notes, abbreviations -	Dimensioning

Errors in these standards will confuse contractors and lead to misunderstanding while pricing the job. The research found that 4% of all errors were this type of errors, which gives bad impression about the designer. Client or contractors may avoid working with such designer.

6.4.2	CADD –related problem These types of errors are related to the capability of CADD (Computer Aided Design and Drafting) software used, setup of the CADD standards and procedures. They are related mainly to coordination problems between files, un-updated background files of other disciplines, which will create errors in the construction documents. The CADD problem increase as the project complexity increase by the reality that more people and even firms will work simultaneously on the same project. Many organisations such AIA (AIA-1994) have recognized the importance of CADD in the process of producing the construction documents and have set up procedure for CADD implementation and usage. Following such procedures will have influence on the productivity of the designer and minimizing this type of error. The research found that 5% of all errors were this type of errors, which might have influence on the duration of the project and raise of claims from the contractor(s), as might need more time to resolve problems and update drawings or preparations of the shop drawings.

6.4.3	Dimensional error Necessary dimensioning should be numerically indicated on the drawings. The contractor is not entitled to rely on scaling the drawings for dimensioning, the drawings should contain the minimum dimensioning consistent with this concept. The dimensions do not add up, conflict of dimension between drawings, details, and schedules. Most dimensional errors found in the case studies refer to errors which could be easily prevented if the proper guidelines for dimensioning are followed. There have been reorganization and attempts to minimize this type of errors in the procedures adapted for documents production (AIA, 1994, p713).

The research found that 4% of all errors were this type of errors, which might effect the duration of the project, as the contractor has to wait for clarification from the designer about the conflicting or missing dimensions.

6.4.4	Symbols and abbreviations errors The need to communicate a great deal of information in a limited space commonly dictates the use of many symbols and abbreviations. Good practice suggests that these be defined early in the documents and used consistently (AIA, 1994). Designations on the drawings should be consistence and be coordinated with those used in the other part of the construction documents, such as schedules, specifications etc. The research found that 3% of all errors were this type of error as the lowest within this category. This type of error will lead to misunderstanding and confusion about the documents which might leads to request for the extension of time due to time wasted waiting for response from the designer.

6.5	Coordination Errors The research found that 13% of all types of errors were coordination problems within or between disciplines. The most occurrences were with the private sector client (61%) and the least with developer client (11%) and it was 28% with governmental client. The traditional procurement showed the highest amount of errors (50%) and the design and build the lowest (16%) and it was 34% with the use of construction management procurement. The following are the two basic type of errors within this category: 6.5.1	Disciplines coordination problems NEDO (1987, p3) states, “ The design process is difficult enough to control when there are several disciplines to bring together, each of which can affect the performance of others. Nigro (1984) who reported that more than half of the errors and omissions in construction drawings and specifications are due to poor coordination between design disciplines Poor design coordination may result from inadequate attention being given to detailed design or it may follow from a general atmosphere of haste surrounding fast-tracked project. While overlap of design and construction can save time for the client, it may cause delays during the construction phase from problems associated with design coordination and design detailing. The research found that 8% of all errors were this type of error. This error is mostly discovered during the quality assurance review process of the documents. Under the traditional procurements, if it is discovered during the construction stage, it will give the contractor the rights for claiming extension of time and/or compensation for extra cost for correction of the drawings. During the tendering stage, if the amount of this type of error is high in the documents, it will raise many queries during the tender stage and give a bad impression about the designer. 6.5.2	Interdisciplinary coordination problem These errors refer to the errors which occur within one discipline e.g. the coordination problem between plans, elevations, sections and the detail drawings, between the calculations and the drawings, or between the drawings and the specifications. The research found that 6 % of all errors were this type of error as the highest within this category and as the second highest within all types of errors. As the amount of the errors is increased in the documents, it will raise many queries during the tender stage and gives a bad impression about the designer. If this type of error is not discovered during the construction document process then it will raise problem later in the construction stage and raise claims for extension of time and sometimes compensation for extra costs.

6.6	Operability problem Even though the research found that only 5% of all errors were this type of error, it is considered as one of the most serious error that related to difficulty of operation and maintenance, this is because the problems often plague the project for many years after the design team has completed the work. The long term effect can be devastating to the design firm reputation. The problem in this type of error that it is normally discovered during the utilization of the project and not during the process of producing the construction documents or during the construction stage. The user(s) of the project either has to live with the error or he has to pay for the expensive cost of replacement. The research found that the developer showed the lowest amount of this type of errors (16%) and private sector client as the highest (53%) and it was 31% in the governmental clients. While the procurement showed close distribution between different types of procurement, as it showed 36% for construction management, 33% for design and build, and 31% for traditional procurement.

6.7	Constructability problem This type of errors was a factor in the development of many strategies in the construction industry, such as Partnering, Concurrent engineering, etc. where contractor(s) participate in the process of developing the construction documents. This problem is related to those designs which are difficult for the contractor to bid or construct. These include specification for equipment, which has not been manufactured for years, and construction sequencing that cannot be done without disrupting ongoing operations. The research found that 4 % of all errors were this type of error. If this type of error is discovered during the construction stage it will often turns into costly change orders. This may influence the budget of the project or cause delay in project completion date. The research indicated that most occurrence of this type of errors are with the private sectors client (51%), the lowest with developer client (17%) and 32% for the governmental client. It was found also that this error are mostly occur with the use of construction management (44%), then in design build procurement (37%) and the last occurrence with the use of the traditional procurement (19%).

6.8	Other type of errors Errors in contract documents were encountered in one incidence and in one project only. It was mainly discrepancy among tender documents regarding the period of contract, bond percentage, insurance sum etc. The following table summaries the occurrences of errors in relation to types of client and the procurement used for the project

7	Data testing The general difficulty of working with samples is that samples are generally not identical to the population from which they were drawn. The statistics collected from samples will therefore differ from the corresponding parameters for the population. Furthermore, the samples are not identical to each other. They are variable because they contain different individuals. Each sample from the same population will have a slightly different sample mean and standard deviation. Measurement of dispersion based on the mean can show the degree by which numerical data tend to spread about an average value and it is called variation or dispersion. It is represented by mean deviation. The other measure of the degree in which data is spread around the mean is the standard deviation. The data should fall approximately into so called "normal distribution". The normal distribution is an important expression as it shows whether the data is normally distributed or not.

To make sure that the data are representative of the population of the construction industry we used statistical procedures – using SPSS software - which will show that the sample are falling - with enough confidence intervals - within the normal distribution

8	Results The following charts summarize the finding of the research. In (chart -1) the result of research showed that “Additional views / details needed” is the most type of errors (9%) occurring in the construction documents and then “callout of the details are incorrect or missing)” is the second highest (8%) type of errors occurring. The lowest type of errors (2%) encountered in this research was “Document does not conform with the law.

8.1	Errors and size of project The research showed also that there no direct link between size of the project and amount of errors occurrence refer to Fig – 4 if we consider the cost of project as an indication of the size of the project.

8.2	Errors and type of client The most occurrence of errors was were occurring in the private sector projects (55%) and the least with developer (12%) ; this is may be due to the QA check in governmental project which normally take place during the process of preparing the documents and the approval process and when the client needs and wants are clear it will lead to less occurrence of errors as the case of developer and governmental clients even though the motive is different i.e. in governmental is imposed by different governmental auditing control agencies and developer for financial purposes, refer to Fig – 3. 8.3	Errors and the procurement used to execute the project The least occurrence of errors were in design and build (23%) as there is only one party to hold the responsibility, then in traditional procurement where the documents are completed before the start of the construction (37%) and the construction documents showed the highest occurrence of errors (40%) as the full documentation is not yet finalized.

8.4	Errors and type of documents reviewed The other issue which was noticed that the types and number of occurrence for the errors discovered in QA set is different from those discovered in tendering queries or the variations order lists, refer to Fig – 5. The same argument applies also to the procurement implemented for the project, refer to Fig – 6. This may be due to that the interest of different project stakeholder are different from one to another, as QA normally check the coordination and consistency of different disciplines together and tender queries normally request answers for those errors which influence the tender price and the contractors may hide some errors for later use to support request for additional money or time extension.

8.5	Classification of Errors Even though the above types of errors look diverse they can be classified into the following classification: Failure to conform to design parameters, Coordination problems, Failure to address operability and constructability issues, Failure to follow procedures of producing the construction documents, Omissions, and Erroneous actions as shown on table-4. The classification adapted in this research indicated that erroneous occurrence are the most type of error occurred in the construction documents (about 23%) then missing items as the second highest (about 22%) and constructability as the lowest type of error occurred during the development of the construction documents. (Fig -2). This observation gives an indication that minimizing the amount of errors generated during the process of developing the construction documents is achievable and applicable.

The following table (table 7) summaries the finding of the research regarding errors and classification in construction documents.

9	Conclusions: To minimize errors you have first to know it, as once an error has been identified it is possible to take action to address it. This research represents some important fact about errors in the construction documents. Even though other researches mentioned and listed different types of errors encountered in the Q.A. process, they did not explained, discussed the influence of their occurrence, their nature or the spread of their occurrence. In this research we have defined errors, discussed and identified many types of errors in the construction documents through thoroughly investigation of 30 case study projects. The errors in construction documents can be classified to Failure to conform to design parameters, Coordination problems, Failure to address operability and constructability issues, Failure to follow procedures, Omissions, and Erroneous actions The observation give an indication that minimizing the amount of errors generated during the process of developing the construction documents is achievable and applicable as erroneous and missing items type of errors are the most type of errors occurred in the construction documents. We have seen that the effects of these errors on the construction documents and later during the construction stage differ depending on the severity of the error and the stage of work when the error(s) was discovered.

References: 1.	The Architect’s Handbook Of Professional Practice, AIA, 12th Edition 1994 2.	Choy W.K. & Sidwell A.C. 1991, `Sources of variation in Australian construction contracts', The Building Economist, vol. 30, no. 3, pp. 25-31. 3.	Diekmann J.E. and Nelson, M.C., (1985), Construction claims : Frequency and Serverity. Journal of Construction Engineering and Management. ASCE 115(3), 385-400. 4.	Langford, V., Fellows R. F., & Newcombe R., (1986), Variations in building contracts: the role of the social system. CIB 86 Advancing building technology, V 8, Translating research into Practice, 3522-30 5.	Love, P.E.D., Li, H. Mandal, P. (1999), Rework: a symptom of dysfunctional supply chain, European Journal of Purchasing and Supply Management, 5(1), 1-11 6.	Love P.E.D., Mandal, P., Smith, J and Li H. (2000), Modelling the dynamics of design error induced rework in construction, Construction Management and Economics, 18, 567-574 7.	Kirby J. G., D. A. Furry & D.K. Hicks, 1988, Improvement in design review management, Journal of construction engineering and management, V114, No. 1 March. 8.	NEDO Construction Industry Sector Group 1988, Faster Building for Commerce, Report prepared for the National Economic Development Office (NEDO) Commercial Building Steering Group, London 9.	Rukn Eldeen, M., 1999, The efficiency of cost control procedures in Saudi Arabia construction projects, MSc thesis, Department of Building Engineering and Surveying, Heriot Watt University, Edinburgh, UK. 10.	Stasiowski F. A., D. Burstein, 1994, Total Quality Project Management for the design Firm,

Type of Project reviewed No of Drawings (Size)	No of errors	Design Fees (SR)	Construction cost (SR in Million)	Stage of drawings Religious / Resident	91 (A1)	217	760,000	9	Final Monumental 	60(A0)	167	600,000	20	Final Site Work 	140 (A1)	146	1,500,000	33	Design development Private Palace 	210(A1)	192	2,000,000	45	Design Development Office Building	100 (A0)	183	375,000	16	Final Table 1 : Pilot Study projects

Type of errors in the construction documents	Stasiowski 1994	Pilot Study	Professional Document does not conform to client's design criteria	 Document does not conform to code		 Document does not conform to design calculations		 Document does not conform to vendor data 	 Document does not confirm to the Municipal regulations		 Document does not conform with the law (such as documents must specify Saudi products)			 Discipline coordination problems (within the same discipline)		 coordination problem (between disciplines)		 Operability problem		 Constructability problem		 Document does not conform to drafting standards		 CADD (Computer ) related problem		 Dimensional error		 Errors in Symbols and abbreviations		 Callouts of the details are incorrect or missing		 Missing or Incorrect notes on the drawings		 Additional views / details needed		 Errors in capital cost estimating errors			 Designer error		 Error in project contextual factors, (not compatible with survey or roads)		 Errors and omission in the bills of quantities		 Errors in specifications		 Table 2 : Comparison between Literature and Pilot Study Errors.

Type of Project	Number Interior Design Project	2 Monumental work 	1 Military	1 Residential	7 Site Work	1 Religious project	3 Shopping	4 Office Building	7 Multi use building (office/Residential Apartment)	3 Multi use building(office/Shopping)	1 Total No. Of projects	30 Table 3 : Classification of case study project

Type of Client	Procurement Type	Type of document reviewed Private	56.67%	Construction Management	29.63 %	All documents	30% Government	36.67%	Design and Build	14.81%	QA	43.33% Developer	6.67%	Traditional	55.56%	Tender queries	20% Variation	6.67% Total	100%	 	100%	 	100% Table 4 : Analysis of case study projects

Conformance errors	Coordination errors	Operability	Constructability	Process	Missing Items	Erroronus Private sectors Client	51.63%	61.11%	53.33%	51.22%	54.86%	57.08%	54.34% Governmental client 	34.64%	27.78%	31.11%	31.71%	34.03%	33.49%	34.70% Developer client 	13.73%	15.58%	15.56%	17.07%	11.11 %	9.43%	10.96% 100%	100%	100%	100%	100%	100%	100% Table 5 : Types of Client and occurrence of errors

Conformance errors	Coordination errors	Operability	Constructability	Process	Missing Items	Erroronus Construction Management Procurement 	48%	34.51%	36.11%	43.75%	43.41%	34.97%	41.49% Design and Build Procurement	28%	15.93%	33.33%	37.50%	21.71%	21.31%	20.74% Traditional procurement	24%	49.56%	30.56%	18.75%	34.88%	43.72%	37.77% 100%	100%	100%	100%	100%	100%	100% Table 6 : Procurement and occurrence of errors

Classification	% Error ID	%	Type of errors in the construction documents	Influence on project Erroneous	23.30%	E15	4.47%	Errors in capital cost estimating errors	Time, cost E16	6.06%	Designer error	Time, cost E19	2.98%	Error in project contextual factors, (not compatible with survey or roads)	Time, cost E20	5.43%	Errors and omission in the bills of quantities	Time E22	4.36%	Errors in specifications	Time, cost Missing	22.55%	E10	7.77%	Callouts of the details are incorrect or missing	Time, cost E12	5.96%	Missing or Incorrect notes on the drawings	Time, cost E13	8.83%	Additional views / details needed	Time Conformance	16.28%	E1	2.98 %	Document does not conform to client's design criteria	Time, cost E2	2.55%	Document does not conform to code	Time, cost E3	3.09%	Document does not conform to design calculations	Time, cost E8	3.83%	Document does not conform to vendor data (elevators, equipments,…)	Time, cost E17	2.02%	Document does not confirm to the Municipal regulations	Time, cost E18	1.81%	Document does not conform with the law (such as documents must specify Saudi products)	Time, cost Process	15.22%	E14	3.83%	Document does not conform to drafting standards	Time E11	5.0%	CADD (Computer ) related problem	Time E9	3.72%	Dimensional error	Time E21	2.77%	Errors in Symbols and abbreviations	Time Coordination	13.40%	E5	5.74%	Discipline coordination problems (within the same discipline)	Time, cost E4	7.66%	coordination problem (between discipline)	Time 4.79%	E6	4.79%	Operability problem	Time, cost 4.36%	E7	4.36%	Constructability problem	Time, cost Table 7 Classification, Types and Spread of occurrence for errors in construction documents