Franco K.T. Cheung

Multi-criteria evaluation model for the selection of architectural consultants

The selection of a competent architect is vital to the success of a development. Like in many developed countries, developers in Hong Kong select architects based on a set of criteria. Price is not the only consideration in the process, and decisions rely heavily on subjective judgement. By conducting a questionnaire survey, the research reported here identified the common criteria for selection and their relative importance for an objective selection. This involved the use of an evaluation method called the analytical hierarchy process (AHP). Survey data from projects with similar characteristics were used to compute the criteria weights. Multi-criteria models for seven out of 27 categories of project were built with reference to the computed weights derived from the survey. In addition, a computer program, called the Architectural Consultant Selection System (ACSS), was designed to illustrate a logical approach for the evaluation of prospective consultant architects based on the models constructed.

A study of clients' and estimators' tolerance towards estimating errors

Previous research on building pre‐tender cost estimating stresses the importance of giving accurate estimates and minimizing estimating errors. Cost models, especially those mathematical models using mean square error or the like for model training and validation, often treat positive errors (overestimates) and negative errors (underestimates) of equal magnitude the same with an implicit assumption that the regret or disutility of positive errors (overestimates) is equal to that of negative errors (underestimates). A survey was conducted in Hong Kong to study estimating practice and in particular, the attitude of clients and estimators towards estimating errors. This involved the use of regression analysis to model the relative disutility of underestimates (in terms of overestimates) for four different building types. Both clients and estimators are found to be risk averse—tolerating overestimates more than underestimates—and, arguably, clients are satisfied with overestimates. However, they have contrasting views on the desired characteristics of estimates with clients considering the ability to identify cost sensitive elements to be more important than accuracy. In this regard, the formalization of value analysis as part of the cost advice function under typical cost consulting agreements should be the best form of improvement.

Explorations in specifying construction price forecast loss functions

Typical measures of goodness of construction price forecasts are the mean and standard deviation, coefficient of variation and root mean square of the deviations between forecasted and actual values. This can only be valid, however, if the pain, or loss, incurred as a result of such deviations is directly proportional to the square of their value. Two approaches are used to test this. The first of these analyses 10 sets of data collected from around the world, while the second explores the use of a postal questionnaire survey to elicit construction industry client disutilities. The results of the first analysis mitigate against any general view that projects tend to be overestimated but do clearly suggest asymmetric under/overestimates for the measures used. The second analysis results in an approximated loss function although in ordinal terms only. This also suggests that the functional form varies between building types, with Commercial and Residential being the most asymmetric and Schools and Industrial being less asymmetric. The work to date indicates that, for construction price forecasting, the loss functions involved are asymmetric, with the degree of asymmetry increasing according to the level of commercial financial viability at stake.

Does the UK built environment sector have the institutional capacity to deliver sustainable development

Globally, the construction sector has to reduce its environmental impact. Institutional innovation is necessary to achieve reductions at the required levels. Robust and rigorous evaluations of the industrys capacity to bring about such innovation are absent, although there is a plethora of policy incentives, and more frequently obligations, for the industry to take action. This paper evaluates the UK construction industrys institutional capacity to innovate to become more sustainable. The industrys current impact on the environment is first illustrated. The second section argues the case for institutional innovation to meet the UK Governments targets, and reviews the policy implementation and institutional innovation literature. A framework that is later used to evaluate the UK construction industrys institutional capacity to deliver sustainability concludes this section. The main body of the paper focuses on this evaluation by using secondary data published by key government departments and industry bodies.. The conclusions identify the policy framework as the strongest aspect of the industry, whilst demonstrating that in other areas, i.e. content, capacity, commitment, and clients and collaborations, there is much room to develop institutional capacity. The fragmented industry structure and the current state of the economy are identified to be the main barriers to development.