Improving accuracy of early stage cost estimation by revising categorical variables in a case-based reasoning model

Jin, R; Han, S; Hyun, C and Kim, J (2014) Improving accuracy of early stage cost estimation by revising categorical variables in a case-based reasoning model. Journal of Construction Engineering and Management, 140(7): 04014025, ISSN 0733-9364

Abstract

For the overall success of a construction project, it is very important to accurately estimate the construction cost from the early stage. However, the limited information available in the early stage makes the cost estimation challenging. Recently, there has been an increase in the use of case-based reasoning (CBR) to estimate construction cost in the early stage. Based on the hypothesis that similar problems have similar solutions, CBR searches for the most similar cases (e.g., previous projects) for a given problem (e.g., a new project). However, because no previous project is exactly the same as a new project, the solutions applied to the past project may not work for the new project, especially when there are no sufficient cases stored in the case base. To overcome this limitation, some studies have highlighted the importance of revision algorithms to account for the deviation of the new project and the identified similar past projects. These studies, however, were limited in considering the deviation of numerical variables while the majority of variables available in the early stage is more categorical (e.g., structural system or underground condition) than numerical (e.g., gross floor area). Based on this recognition, this paper presents a revision method considering the deviation of categorical and numerical variables using regression analysis. Application to multihousing projects confirmed that the proposed CBR model can increase the accuracy of construction cost estimation. This paper is of relevance to researchers in terms of providing a theoretical basis to incorporate both numerical and categorical variables in revising the CBR model. This paper is also of value to practitioners with regard to providing an accurate cost estimation tool in the early stage of construction projects.

Item Type: Article
Uncontrolled Keywords: case-based reasoning; categorical variables; cost and schedule; cost estimation; regression analysis
Index terms: estimate, regression analysis, deviation, construction cost, gross floor area, estimation, construction project, practitioner, accuracy, case-based reasoning, cost estimating
Subjects: statistical analysis, cognitive psychology, building performance, production management, professional development, financial and cost management, practitioner
Topics: Design Practice, Roles and Professions, Information Management, Project Management, Research Practice, Cost Management
Descriptive scope: 4 PCTA

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