A commercially available crime index may be a reliable alternative to actual census-tract crime in an urban area

Health research on the effects of crime has been hampered by a lack of small-scale, reliable crime data. Our objective is to assess the accuracy of a set of commercially available crime indices for use in health research. The 2016 release of Applied Geographic Solutions' (AGS) crime indices are based on data from 2010 to 2014 and provide tract-level information on crime. We use crime rates for 1069 tracts of the Los Angeles Police Department (LAPD) jurisdiction for the same years to assess (1) Spearman Correlations of major crime categories, and (2) accuracy of AGS indices in predicting falling above/below the median and into the highest/lowest quartile of LAPD crime. We also test if adding variables from the American Community Survey (ACS) to regression analyses can help to reduce measurement bias. We found that five of ten AGS indices correlated moderately well with LAPD crime. In unadjusted regressions, robbery, homicide, aggravated assault, motor-vehicle theft and personal crime achieved c-statistics from 0.81 to 0.90. C-statistics improved up to 0.13 points after adding ACS variables. Some AGS crime indices may be reliable proxies for crime in an urban area. The AGS index for total crime, most commonly used in prior research, performed poorly.