The most important thing about ideal types is that they are heuristic devices; they are to be useful and helpful in empirical research and in helping us understand the social world. As lachman said, an ideal type is “essentially a measuring rod” (1971:26). Here is the way weber put it: “its function is the comparison with empirical reality in order to establish its divergences or similarities, to describe them with the most unambiguously intelligible concepts, and to understand and explain them causally” (1903-1971/1946:43). Ideal types are heuristic devices to be used in the study of slices of historical reality. For example, social scientists would construct an ideal-typical bureaucracy on the basis of their immersion in historical data. This ideal type can then be compared to actual bureaucracies. The researcher looks for divergences in the real case from the exaggerated ideal type. Next, the social scientist must look for the causes of the deviations. Somc typical reasons for these divergences are: