open data

Why you can't identify changes in crime by comparing this month to last month

This post first appeared on the Social Research Association blog. Understanding if some event is associated with a change in the frequency of crime is a common question, both in practice and in research. A crime analyst might need to understand the impact of a change in tactics, a local journalist might want to check the truth of the mayor’s claims that her policies are working, while an academic might seek to find patterns associated with trends in socio-economic changes.