This study analyzes the genealogy of farmhouse economy investigations (農家經濟調査) conducted by colonial power in colonial Korea, focusing on the aspect of conceptualization and categorization of investigations. Farmhouse economy investigations implemented in colonial Korea adopted research techniques of Japan at that time. They were based on the theory of small farmer’s economy (小農經濟理論) proposed by a Russian agricultural scholar, Alexander Chayanov. Especially, the investigation (1930-1933) carried out by Chosen Agricultural Association had crucial impacts on colonial agricultural policy in the 1930s. Through this investigation, the Governor-General of colonial Korea found out that there were large amounts of surplus labor power in colonial rural society. Self-reliance movement (自力更生運動) was carried out, based on the principle that it would be possible for farmers to make ends meet by replacing wage labor with family labor. However, the formula calculating the size of surplus labor power was not based empirical investigations. In other words, it was not based on a scientific premise. On the basis of this study, the colonial state had proposed a vision of spirit-mobilizing hard work and austerity. “Abstract hypotheses” proposed by the colonial state was recognized as “objective evidence” and defined the direction of social policy, because it was impossible to conduct alternative and critical investigations. This urges the social scientists to reflect upon their own work in using historical documents and pay attention to political meanings of investigations.