The central paper of the thesis analyses witch trials in Europe. In addition to developing a new witch trial dataset and providing new support for the income-agriculture and persecution channel, we also break new ground examining the roles that plague and war have to play. Underlying these witch trials is human behaviour, based on self-interest. This paper links to the other two papers. Firstly there is the paper which analyses how researchers deal with missing data. It became apparent whilst researching the witch trials paper that missing data was a major problem in economic history and one that had been analysed with relatively simple, and unsatisfactory techniques. This led me to research how other disciplines have responded to problems of missing data and then develop my own approach within the context of Scottish medieval commodity prices. The third paper also analyses human behaviour but in the context of workplace peer effects, in professional golf tournaments. All three papers are empirically focused.