An Evaluation of The Budgetary Reliability of Bills of Quantities In Building Procurement

Bills of quantities have been documented to exist in some form or another as far back aswhen the Egyptian pyramids were being constructed. In spite of that age long history, thebills of quantities (BOQ) seems to be the most misinterpreted aspects of buildingdocumentation today. The pros and cons of the bills of quantities have been deliberatedon for many years and have generated strongly held and differing views. Whilst this isrecognised, the essence of this study is to evaluate the reliability of bills of quantities inbuilding project procurement. The study was carried out using secondary data from somerecently completed building projects within the Northern Ireland construction industry.Using secondary data from completed projects, the budgetary reliability of the bills ofquantities in building project procurement was investigated. Data analysis was carried outusing percentage deviation of final account figures from the bills of quantities. Furtheranalyses were carried out using root mean square deviation and relative mean absolutedeviation methods of analyses. Results showed that the budgetary reliability of the billsof quantities seems to vary depending on project types. Whilst a deviation of -3 to 4%was obtained on housing projects analysed, the deviation on educational projects wasbetween -4 and 17% whist on commercial project, it came out to be between -20 and 20%and in the case of refurbishment projects, a deviation of between -11 and 37% wasobtained. This seems to suggest that the more complex a project is, the less reliable it is touse the BOQ to guarantee cost certainty.