Testing for seasonality in reported crime data

In spite of the apparent importance of crime statistics to policy-makers and the public, these data are not often analyzed or refined in the same manner as other social series such as unemployment. In this paper, seasonal variation in FBI index crimes is investigated for a major urban area. Using Miami data for 1949–1970, a test for seasonality is developed and seasonal indices are constructed for a number of crime types. A definite seasonal pattern in Miami crime data is found to exist, although its importance seems to be declining in recent years. Some applications of seasonally adjusted data to public information and operations are also briefly discussed.