Guide to Cost Predictability in Construction: an Analysis of Issues Affecting the Accuracy of Construction Cost Estimates
Total Page:16
File Type:pdf, Size:1020Kb
Guide to Cost PrediCtability in ConstruCtion: an analysis of issues affeCtinG the accuraCy of ConstruCtion Cost estimates Prepared by the Joint Federal Government / Industry Cost Predictability Taskforce november 2012 Guide to Cost Predictability in Construction: An Analysis of Issues Affecting the Accuracy of Construction Cost Estimates November 2012 Table of Contents Note from the Taskforce Chairman . 1 Executive Summary . 2 Taskforce Participation . 3 Introduction to the Cost Predictability Issue . 4 Issues and Considerations in Cost Predictability . 6 Cost Estimate Variance Matrix . 9 Recommendations for Improved Cost Predictability . .10 Postscript . .11 Appendix 1 – Classes of Estimates . .12 Appendix 2 – Documents Recommended for Estimates . .14 Appendix 3 – Qualifications for Estimators and Cost Consultants . .21 Appendix 4 – Sources of Information and References . .24 Enquiries should be directed to: Canadian Construction Association www.cca-acc.com This guide is the product of the individual taskforce members’ collective input and does not purport to express or represent the position of their respective organizations or associations. It reflects recommended industry practices. Readers are cautioned that this guide does not deal with any specific fact situation or circumstance. This guide does not constitute legal or other professional advice. The taskforce and their respective organizations or associations do not accept any responsibility or liability for loss or damage which may be suffered as a result of its use or interpretation. Copyright 2012 Must not be copied in whole or in part without the written permission of the Joint Federal Government / Industry Cost Predictability Taskforce. Guide to Cost Predictability in Construction: An Analysis of Issues Affecting the Accuracy of Construction Cost Estimates November 2012 Note from the Taskforce Chairman associated degree of accuracy of the estimate can be expected to vary accordingly. What at first appeared to be a relatively simple task to review the various and mostly obvious causes of poor For this reason the taskforce concluded that the previously cost predictability increasingly grew in each taskforce accepted degree of accuracy for Class A estimates should meeting as more and more variables were raised and be expanded from +/- 5% to a range of +/- 5 to 10%, to reviewed. As the topics for consideration ranged from accommodate the range of such non-standard projects, first bid comparison, whether low, median or average, to with a similar variation applied to the other classes of cost growth during construction, to final project cost, and estimates. As well, for projects involving significant even whether to review various “soft costs” to the extent renovations, or challenging geographic, environmental, or that they may have an effect on cost predictability, etc., other unique circumstances, a further allowance should be it soon became apparent that a clear and rigid definition analyzed and included. of the scope of the taskforce had to be established. This would limit the discussions to achieve definable In addition, whereas the previous cost predictability recommendations relating to the original rationale for guidelines were related primarily to the degree of design the taskforce, which was to analyze the increasingly large development completion, it became obvious that with the variances being experienced by PWGSC, DCC, and others increasing variety and complexity of various projects, the between their “pre-tender estimate” and the subsequent potential accuracy of estimates must equally recognize contractors’ bids. the relationship to the level of complexity of any particular project, or its level of estimating difficulty. For this reason, a The basic question whether such increasing variances Cost Estimate Variance Matrix was developed, to recognize are the result of the construction industry’s “pricing the combination of both these dimensions in arriving at a strategies”, or of an inaccurate or insufficient estimating reasonable estimate variance. process, was soon concluded to be the latter, since with few exceptions, under a normal and competitive bidding Finally, since estimating and bidding is not an exact process actual bid prices are generally the best indicator of science, the expectation for estimate accuracy must be the prevailing competitive market conditions for a specific realistic, in relation to the particular type of project and in project at that time. Upon further review it was also found proportion to the quality and time expended to produce that the owners’ estimating process was seldom properly a specific level of estimate accuracy. But at any level, completed up to a reasonable Class A level, and in most adherence to the recommendations of this guide should cases only up to Class B, or even a brought forward Class C! definitely improve cost predictability. Also, it must be recognized that each project is unique In this respect it bears repeating the obvious, that to and different from the previous one in varying degrees. achieve a realistic Class A estimate requires the following Although many projects may be relatively repetitive and ingredients: “similar”, such as “standard” office buildings or schools, 1. Class A professional and experienced estimating many others are non-standard and individually complex, qualifications; unique, one-of-a-kind, remotely located, etc., or any combination thereof, such as leading edge lab facilities, 2. Class A completed project design documentation; and historic building renovations, environmentally challenged 3. Class A time, sufficient to produce the required estimate locations and increasingly green, sustainable, and more analysis with accuracy. innovative structures and systems. Lastly, the taskforce was fortunate to have the benefit of Further, since the preparation of project estimates has senior, experienced, informed, articulate, and independent typically been based on historical information, such cross-sector representatives; I sincerely want to thank each information may be outdated, or perhaps not even exist of them for their effective and dedicated participation in for certain individual types of projects; therefore, the the production of this guide. 1 Guide to Cost Predictability in Construction: An Analysis of Issues Affecting the Accuracy of Construction Cost Estimates November 2012 Executive Summary • recognize the degree of accuracy of the estimate being used. Large discrepancies between pre-tender estimates and actual bids for construction have a serious impact on A large number of factors contribute to variances in the viability of a project. Owners, architects, engineers, estimate to bid prices. This guide will provide practical cost consultants, contractors and subcontractors all advice and discuss the primary ways to improve the cost have a vested interest in ensuring a high degree of cost predictability of projects. The consequence of a failure is predictability. This issue, raised at the Federal Government often a cancelled project. / Industry Real Property Advisory Council, resulted in the formation of a Cost Predictability Taskforce, to research and The Cost Estimate Variance Matrix recommend solutions to this increasing problem. As shown in the Cost Estimate Variance Matrix, the accuracy of estimates varies throughout the project design Defining Cost Predictability cycle and according to the complexity of the specific For the purpose of this guide, “cost predictability” is project, and several other factors that may be unique to defined as “the prediction of a construction cost estimate, a project. Depending on the class of estimate and the as compared to the median of competitive bids”, where complexity of the project, variances can range from 5% to “prediction” is defined as “an assertion on the basis of data, 30%. If additional unique aspects or risks apply to a project, theory or experience, but in advance of proof”. these variances should be analyzed and increased by an appropriate amount. As such this guide will apply only to procurement processes that typically require the submission of a total Improving Cost Predictability project bid, such as a design-bid-build or design-build Early in the project life cycle, i.e., before the requirements process, and although not directly applicable to the are well-defined and before accurate estimates are construction management process, it could also be applied available, owners will need to set budgets. The challenge to the sequential trade contractors’ bids. for all stakeholders is to ensure that the appropriate scope and cost management framework is adopted to ensure Similarly, many of the same underlying principles could the desired, or required, degree of cost predictability. The also be applied to the further development of cost following recommendations should be considered to predictability guides for the increasing range of P3 and improve the cost predictability between the final pre- lease/purchase procurement process variations. tender estimate and actual bid prices: Taskforce Analysis Before Tender There is no common statistical database on variances • include sufficient contingency to address market between pre-tender estimates and final bid results for volatility, timing of construction, and other exclusions in the Canadian construction market. However, members the estimate; of the task force shared internal data that showed up to 40% of tenders had low bids that varied, either up or • consider possible scope