TREND AND DEVIATION IN CRIME RATES: A COMPARISON OF UCR AND NCS DATA FOR BURGLARY AND ROBBERY*

Abstract

Trends and year‐to‐year deviations in UCR and NCS data on burglary and robbery are examined for the period 1973 to 1985. We find strong correspondence between year‐to‐year deviations in UCR crime rates and NCS victimization rates for both crime types. The difference between the two data series lies primarily in their contrasting trends, although there is some evidence that trends in UCR and NCS crime rates have been converging in recent years. Ex post forecasts reveal that the UCR/NCS relationships estimated from the 1973–1985 data continued through 1986 and 1987. Although the UCR rates in 1986 were somewhat influenced by unusual increases in the proportion of crimes reported to the police that year, changes in crime reporting for the period as a whole have had little effect on UCR burglary and robbery rates. We conclude that, within the two serious crime types examined in this study, there is strong consistency between the alternative data sources on variations in crime rates over time.