Categorization plays an integral part in how we see and interpret the world. This is especially true when we attempt to comprehend the complexities of human society, where the heterogeneity of human activity across time and space demands that some criterion (class, gender, age, profession, etc.) be used to reduce the number of variables examined. From the mid-nineteenth century—as statistics evolved from the simple “political arithmetic” of tax collectors and army recruiters into a potential science of human behavior—categorizing the population became a contentious issue that reflected the social and political agendas of data collectors.Theodore M. Porter, The Rise of Statistical Thinking, 1820–1900 (Princeton, 1986); Stephen M. Stigler, The History of Statistics: The Measurement of Uncertainty before 1900 (Cambridge, MA, 1986); Stuart Woolf, “Statistics and the Modern State,” Comparative Studies in Society and History 31, no. 3 (July 1989): 588–604; Ian Hacking, The Taming of Chance (Cambridge, 1990); William Alonso and Paul Starr, eds., The Politics of Numbers (New York, 1987); Bernard S. Cohn, Colonialism and its Forms of Knowledge: The British in India (Princeton, 1996); Benedict Anderson, Imagined Communities: Reflections on the Origins and Spread of Nationalism, rev. ed. (London, 1991), ch. 10, “Census, Map, Museum”; idem, The Spectre of Comparisons: Nationalism, Southeast Asia and the World (London, 1998), 29–45. At the same time, when data refused to be molded to researchers' assumptions, the task of putting people and their activities into analytical categories challenged the validity of the categories themselves. In this way, statistical representations and categories became socially constructed knowledge.