Decision-making within the building industry often involves various criteria of very different natures. Some are qualitative, others quantitative, some are objective, others subjective, but ultimately, they should all be aggregated and handled holistically in order to support decision-making. This process can also be referred to as multicriteria decision-making (MCDM). Some aspects of MCDM are often conducted unconsciously and non-transparently. By implementing mathematical methods that have been proved applicable for MCDM, multi-criteria decision-making processes can be handled more consciously and transparently and thus be made reproducible. The calculation method presented allows quantitative sustainability and qualitative indicator values to be accounted for with the level of importance desired.
The MCDM method used is Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). As the model has already been described well in the scientific literature and is used frequently, the aim is to illustrate how TOPSIS can be applied for transparent decision-making within the building industry in the context of urban renewal and refurbishment schemes through case studies of various scales and descriptions.
The case studies focused on in this paper incorporate a variety of specific prechosen criteria, including environmental performance, functional parameters and technical parameters. The case studies cover different parameters of refurbishment in a major hospital compound in Denmark due to be taken out of operation. One central design decision is whether to refurbish or demolish the old hospital buildings.
The results reveal that decision support is first of all dependent on how the decision-making tool is applied and what choices are made in relation to the actual calculations. However, by implementing a mathematically based MCDM method like that being assessed in the case studies presented, the decisions and their arguments become transparent and are easily communicated within a project group. As a result, the tool is considered to be universally applicable across most decision-making contexts within the building industry.