Otis Dudley Duncan and Andrea Tyree, he co-authored The American Occupational Structure, which provided a meaningful sociological contribution to the study of social stratification, and won the highly touted Sorokin Award from the American Sociological Association in 1968. Blau is also known for his contributions to sociological theory. Exchange and Power in Social Life (1964) was an important contribution to contemporary exchange theory, one of Blau's distinguished theoretical orientations. The aim of this work was "(to analyze) the processes that govern the associations among men as a prolegomenon of a theory of social structure". In it, Blau makes the effort to take micro-level exchange theory and apply it to social structures at a macro-level. Blau was also very active in the study of structural theory. Blau's 1977 book, Inequality and Heterogeneity, presents "a macro sociological theory of social structure" where the foundation of his theory "is a quantitative conception of social structure in terms of the distributions of people among social positions that affect their social relations". Blau received notable distinctions for his achievements, which include: election to the National Academy of Sciences, the American Academy of Arts and Sciences, and the American Philosophical Society. He also served as the president of the American Sociological Association from 1973 to 1974. He died on March 12, 2002, of acute respiratory distress syndrome. He was eighty-four years old. Theory For Blau, sociological theories were produced through logical deduction. Blau began theoretical studies by making a broad statement or basic assumption regarding the social world, which was then proven by the logical predictions it produced. Blau claimed these statements could not be validated or refuted based on one empirical test. Instead, it was a theory's "logical implications" that could be trusted, more so than an empirical test. Only if continued empirical tests contradicted the theory could the theory be modified, or dropped entirely if a new theory was proposed in its place. Blau's trust in logic and his deductive approach to social theory aligns him closely with the philosophy of positivism and traditional French sociologists, Auguste Comte and Émile Durkheim. Blau also focused his sociological theory on both the micro and macro level, and often connected the two throughout his research. Population structures Population structures and their relationship with social interaction was another primary interest within Blau's work. Blau believed that population structure created guidelines for specific human behaviors, especially intergroup relations. Blau