Application of treemaps to the analysis of competitively bid project cost overruns

T. P. Williams

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Purpose – Competitively bid construction projects are often completed for amounts greater than the original low-bid amount. Improved methods of predicting a projects potential to experience large cost overruns would be useful to government agencies for planning capital budgets. The purpose of this paper is to explore the application of treesmaps to the analysis of competitively bid project cost overruns. Design/methodology/approach – In this research a data visualization technique called treemaps was explored as a method of describing the nature of the bids for highway construction projects, and as a method of relating the characteristics of a projects bids to the observed increase in completed project cost. Ratios were calculated that measured bid characteristics for projects from Texas and California. Treemaps were constructed that related the level of the bidding ratios to the level of the difference between the completed project and the original low-bid amount Findings – It was found that the treemaps indicated that projects with high-ratio values typically experienced a larger weighted average percentage difference between the low bid and completed project cost than projects with low ratio values. Research limitations/implications – Future research should include consideration of other project factors in the treemaps, and testing of the treemaps to determine their usefulness to practitioners. Practical implications – Treemaps present a way of understanding complex relationships between construction bidding data and the cost increases that occur during construction without the need to construct complex mathematical models. Originality/value – The paper shows that bidding ratios can be used as indicators of a projects potential for cost overruns. The paper presents a new way of visualizing the construction bidding ratio data.

Original languageEnglish (US)
Pages (from-to)340-356
Number of pages17
JournalConstruction Innovation
Issue number4
StatePublished - Oct 16 2007

All Science Journal Classification (ASJC) codes

  • Control and Systems Engineering
  • Computer Science(all)
  • Architecture
  • Civil and Structural Engineering
  • Building and Construction


  • Construction operations
  • Cost estimates
  • Data handling
  • Project management
  • Visual media


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