The aim of this paper is to assess the link that exists in practice between comparative methods and theories. The paper puts these to the test in the field, based on several experiences of comparison of public policies that combined quantitative and qualitative methods. Their combination refers to actual processes whose complexity is generally obscured in the presentation of the results. Between epistemology and rational conclusions, a component is often lacking, namely the concrete learning of the comparative approach as well as its uncertainties, the doubts it generates, and the difficulties of various types it presents. Yet this dimension of comparative research, including the challenges and opportunities it offers, is crucial for the analysis of public policies as work in progress. The need for a methodological framework arises from the distinction made by Charles Ragin, who asks most of the questions that have to be considered in practice. The various lessons drawn from the comparative experience are then presented based on both international and intra-national dimensions of comparative research. Finally, the lessons drawn from the comparative experience lead us to highlight the strategies of displacement and misrepresentation that, paradoxically, unite the objects, perceptions, and methodology of comparative analysis.