Multi-purpose decision making and investment decisions in the construction industry

The construction industry has a significant impact on production and employment processes, with hundreds of business lines. The construction industry, which has a great national and international potential, can actively mobilize more than 200 sub-sectors (construction materials, finance, business and construction machinery, technical consultancy services, etc.) related to it. At the same time, the construction industry provides employment opportunities in different professions. The construction sector has a very important place in the country's economy with the added value and job opportunities it creates. In this thesis, the constraints and issues that should be considered when making the best investment decision for Build-Sell, Unit Price Contracted and Turnkey Contracted projects that can be done in the construction sector are examined. In the prepared study, it is seen that the projects are beneficial to decide which project can be done under which constraints. Multi-criteria decision making methods have been examined to ensure that the best investment decision is made. For this purpose, 8 expert public, private sector and project managers were surveyed. The AHP method was preferred because it reduces the subjectivity by making the data usable based on the questionnaire and constraints and examining whether these data are consistent or not, and the TOPSIS method because it compares the differences and distances between the projects. With the data analysis, it has provided results that will help companies take the best project investment decision under the constraints they consider important. Keywords: Analytical Hierarchy Process, Construction Investment Decisions, Multi-Criteria Decision Making Methods, Project Selection, TOPSIS.