Research has shown that differences in decision making processes may explain differences in entrepreneurial effectiveness. Particularly rational planning based processes have been set off against other processes such as effectuation, abduction, and bricolage. However, there is still little empirical evidence on entrepreneurial decision making in the earliest phases of enterprise development. In a “living lab”, this study attempts to fill this void, by real-time tracing of entrepreneurs who start in the opportunity recognition phase. This paper shows the first results.