Sousa, V; Almeida, N M and Dias, L A (2014) Role of statistics and engineering judgment in developing optimized time-cost relationship models. Journal of Construction Engineering and Management, 140(8): 04014034, ISSN 0733-9364
Abstract
When estimating the duration of the construction stage during the design stages of construction projects, empirical models are often used as a substitute for more accurate estimates based on detailed scheduling. These models, traditionally designated as time-cost relationships (TCR), derive from regressions relating the duration of concluded construction projects with characteristics that can be easily foreseen during the planning and design stages - both quantitative (e.g., cost, gross floor area, number of floors) and qualitative (e.g., type of contract). This paper reviews the approaches that have been adopted to develop the TCR models and discusses the complementary roles that statistics and engineering judgment can play towards their optimization and enhanced accuracy. This discussion includes the statistical and practical implications of (1) the quantitative independent variables used, (2) the qualitative independent variables used, and (3) the mathematical structure used. The paper aims at demonstrating the importance of sound statistics and highlights some of the most common mistakes. Additionally, it provides illustrative examples to show the complementary role that engineering judgment should have in the process of developing more robust, reliable, and accurate statistical-based TCR.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | construction project scheduling; cost and schedule; engineering judgment; regression; statistics; time-cost relationship |
| Index terms: | statistics, estimate, duration, judgment, gross floor area, independent variable, design stage, construction project, estimating, scheduling, accuracy |
| Subjects: | statistical analysis, building performance, project controls, professional development, production management, financial and cost management, professional practice, operations research, dispute resolution, mathematical modelling |
| Topics: | Cost Management, Research Practice, Project Management, Information Management, Legal Issues, Design Practice, Time Control |
| Descriptive scope: | 3 PCA |
N.B. Descriptive scope is a count of how many of the five facets of empirical research are indicated by the words used in title, abstract and keywords. It is not intended as a judgement on the research; merely a count of the kind of word we would expect to indicate Phenomenon, Concepts, Theoretical framing, Empirical techniques, Analytical techniques. If all five are present, then a code of “5 PCTEA” will indicate this. If you feel the coding for this record is questionable, we welcome discussion around the terms we matched or the way we categorized them. The facet you would expect may not be coded, or a facet may be coded inappropriately. This can also bear on a larger question, of which facets should be treated as defining in construction management research. Please get in touch, and we will look at it. More details here