Purpose: Decision making can be considered as a core part of management science and management practice. However, there still is a lack of understanding as to which major success factors in the decision making process will ultimately lead to better decision making outcomes. In this context, the thesis investigates the impact of the major success factors in the decision making process, defined as the decision making process maturity, on the decision making outcomes, defined as the decision making efficiency, by focusing on the strategic supplier selection process in manufacturing enterprises as an exemplary task of decision making in business management. Moreover, this research analyses the moderating effects of company-internal determinants in the strategic supplier selection process.

Research Design/Approach: The thesis is grounded in the notion of “critical rationalism” which implies that the stepwise deduced theoretical framework has to be tested in an empirical environment. The empirical evidence is gained through a laboratory experiment and through a field study with manufacturing enterprises. Furthermore, the author has executed a variety of statistical procedures by using state-of-the-art software technology (e.g., structural equation modelling).

Findings: The main findings of this research support the basic hypothesis that there is a significant impact of the decision making process maturity on the decision making efficiency in the strategic supplier selection process. The applied statistical procedures provide significant evidence in support of this claim: The laboratory experiment shows a significant impact of the decision making process maturity on the decision making economic efficiency and a highly significant impact on the decision making socio-psychological efficiency. Likewise, the field study indicates a highly significant impact of the decision making process maturity on the decision making economic efficiency and a highly significant impact on the decision making socio-psychological efficiency. Surprisingly, the tested company-internal determinants such as the manager´s experience, manager´s education, and company´s reward initiatives did not significantly affect the strategic supplier selection process.

Originality/Value: The author creates a new construct of the decision making process maturity, which goes beyond actual state-of-the-art concepts, and introduces a holistic approach to measure the decision making efficiency as well. Furthermore, the thesis contributes to the research on descriptive decision making theory by focusing on the strategic supplier selection process in manufacturing enterprises, where empirical research is particularly scarce.

Keywords: decision making, decision making process maturity, decision making efficiency, strategic supplier selection process.