Investigation of contractor selection criteria and development of contractor classification model: a UK case

"Contractor selection practices in UK construction industry have long been criticised. Evidence shows a divergent use of selection methods and different preferences during selection exercises. Albeit, many are adopted and comply with good guidance practices and recommendations from construction reports and commentators. This research focused on UK construction clients contractor selection preferences i.e. prequalification criteria (PC) and project-specific criteria (PSC), and development of contractor classification models to assist construction clients decision-making during tender evaluation. The research also placed emphasis on identifying current selection practices, and gives recommendations to standardisation of contractor selection practices. Tracing client selection preferences and behaviours are the main focus of this research. However, attention also emphasised contractors views upon selection, from prequalification to invitation-to-tender. The pilot (questionnaire) survey findings identify factors affecting clients non-use of standard prequalification practices, particularly, the conflicting views regarding Latham s recommendations (standardisation of contractor prequalification). A second questionnaire survey was conducted to collect information regarding the use of PC and PSC both for building and civil engineering projects from UK construction practitioners. Quantitative analysis of these data from public clients, private clients and contractors represents an in-depth study of these selection criteria and their levels of importance assigned (LIA) by construction practitioners. Significant views and differences on LIA for each selection criteria, and with respect to various selection settings were identified. A multivariate discriminant analysis (MDA) technique is used to classify and predict good and poor contractor groups. The technique used in contractor classification is fully elucidated via sixty-eight case studies of both (completed) building and civil engineering projects; by the first Z1 model and subsequently the (main) Z2 model. The models were tested using independent samples and have been found to have a high degree of accuracy in contractor performance classification."