【正文】 rties involved in the assessment process allow the tool taking into consideration not only the longterm environmental and economic impacts of the building design options but also the feasibility evaluation of the practitioners. Their data are finally integrated intoa single measurement to rank the design options. The integrated tool includes the following steps:1. Generating sustainable building design options through literature review.2. Feasibility assessment by practitioners through educational workshops.3. Technical analysis on life cycle costs and risk levels of design options by technical experts.4. Multicriteria decision making process to bine multiple evaluations by direct weighting method.. Generating design options The sustainable design options are generated by an indepth literature review on the previous researches and established sustainable design assessment tools. The crossmapping method has been applied to summarise a generic and prehensive design option list. According to the design scope and local environment of the individual project, some options that are not applicable are omitted in order to generate a shopping list for the specific project. Those sustainable design options are presented to the practitioners during workshops in order to educate the decision makers about the influence of their decision making on the environment so that they will take more social responsibility. They will also be requested to evaluate the feasibility of the design options on the shopping list under industrial environment.. Data collection The selection of the optimum sustainable design options in the project depends on multiple factors such as: the political concerns of the retailer and the technical issues including life cycle costs and risks. The data e from several parties in the following steps. The first section involves a group decision making process. Workshops with some key executives of the retailer have been arranged on a weekly basis in order to evaluate feasibility of the design options under industrial environment. A questionnaire is designed for the workshops to help the practitioners to rank the options according to the retailer’s priorities. A duepriority matrix has been designed to collect the group decisions for the workshop as shown in Fig. 1. Each of the practitioners evaluates the given options by two priorities: the environmental benefit and the ease of implication. The environmental benefit of the options can be assessed by a 3point scale from low to high. The ease of implication can be assessed by another 3point scale from easy to hard. The decision makers in the workshop will tick the appropriate box in the matrix to evaluate each option.For example, the question to ask the practitioner in the interview survey for each design option is:Environmental Benefit Low High Ease of Implaementation Easy Hard Fig. 1. Duepriority matrix.N. Wang et al. / Building and Environment 45 (2010) 1415–1421 1417 ‘‘For design solution option 12, how to evaluate the ease of implication and its environmental benefit in practice?’’ (please tick the appropriate choice from Fig. 1). Each of the nine boxes in the duepriority matrix represents a number so that the overall feasibility score of the option can beobtained. The scoring system designed for the duepriority matrix is shown in Fig. 2. The final result of the workshop is decided by the overall feasibility score Sw of each option, which is calculated by summarising each of the decisionmakers’ score on the ith option Si divided by the number of decision makers. Sw XSi=n (1) The feasibility of the suggested design options can be ranked by the preferences of the decision making group. Another data collection step involves technical evaluation of the life cycle costs and risk levels of the design options. The experts evaluated the options against these criteria based on their experience and historical data. For each option, the life cycle cost evaluation includes the estimates of the initial capital expenditure and operational cost which are scored according to the cost ranges they fall in. As it is the initial stage of the project development, it is impossible to give a very accurate cost estimate without detailed design information. The quantity surveyor can only give a cost range for each option. The 10 main executives from the retailer, professional quantity surveyors and engineers have been consulted inorder to generate the appropriate scales to measure the performance of each design options. The acceptable levels for additional capital cost and operational cost on top of original budget are ￡5000 (about 1% of project value) and ￡2500 (% of project value) and the most preferred additional cost is nil or ine (negative cost). Therefore the cost ranges surpass the acceptable level were given negative scores. The scoring system for additional capital expenditure (additional cost to development) Scc and operational cost (additional operational cost) Soc is shown in Table 2. The risks that the design option brings to the project are assessed by risk Sr band which then are scored according to Table 3. The measurement of risks to the investor adopts the monly used formatdlow, medium and high level, which are scored as _1, 0 and 1. The advantage of using scoring system is that it significantly reduces the amount of time in estimating a precise cost and can still achieve a ranking function for the design options. . Multicriteria decision making Since this decision making problem involves only a few criteria and they are not interdependent to each other, the direct weighting method is adopted. The output from the workshops and the quantitative analysis are integrated to an overall score for each design option. The feasibility score bines the opinions of all practitioners in the workshop. The score involves two criteria: the ease of implementation and the environmental benefit. The contribution of this sc