Theoretical sampling is the process of data collection for generating theory whereby the analyst jointly collects, codes, and analyzes his data and decides what data to collect next and where to find them, in order to develop his theory as it emerges. The basic criterion governing the selection of comparison groups for discovering theory is their theoretical relevance for furthering the development of emerging categories. Since groups may be chosen for a single comparison only, there can be no definite, prescribed, preplanned set of groups that are compared for all or even most categories. The sociologist should also be sufficiently theoretically sensitive so that he can conceptualize and formulate a theory as it emerges from the data. Theoretical sensitivity of a sociologist has two other characteristics. First, it involves his personal and temperamental bent. Second, it involves the sociologist's ability to have theoretical insight into his area of research, combined with an ability to make something of his insights.