Rationalisation of design cost estimation in the construction industry

  • David J. Blackwood

    Student thesis: Doctoral Thesis


    This thesis describes a programme of research work which investigated the potential for the application of rational approaches, using historic cost data, to the determination of realistic fee estimates for design work in the construction industry. The development of the following research methodology for the programme of work, which was initiated at the request of industrial collaborators, is described and justified.

    A survey of design practices is described that enabled a model of the cost estimation process to be developed. This was tested using a large sample of design organisations and proved to be valid. There was clear evidence in the survey of a polarisation in the use of two forms of cost estimation, with intuitive approaches being used frequently and rational data driven approach being seldom, if ever, used. It was also shown that there was a widely held view amongst designers that design work was not suited to accurate cost estimation and rigorous cost control and, consequently, design organisations had not developed links between their cost control and estimating systems.

    Case studies are described which investigated the practicality of implementing an integrated cost monitoring system for single projects that would produce historic cost data. It was concluded that this was possible for individual projects, but the cost monitoring aspects of the spread sheet system proved to be too cumbersome to be applied to all projects within an organisation.

    The development of a general simulation model of design cost estimation is described which used data from the case studies. A procedure for the application of the model to other projects was devised and the performance of the model was verified by its application to a further project. It was concluded that the model provided a realistic prediction of the required resource input for the project.

    Finally, the principal conclusion from the research work is described, namely that the potential for rationalisation of design cost estimation is severely limited in design organisations because current design management practice has restricted the availability of relevant historic data. However the success of the data collection and cost modelling stages of the work indicated that further research in these areas would be valuable.
    Date of AwardJan 1998
    Original languageEnglish

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