The town of Richmond, California has become somewhat of a poster child for US law enforcement recently, thanks to the former police chief’s support for the #BlackLivesMatter movement. Richmond is still in the worst 10% of US cities for crime, but the crime rate (and particularly the murder rate) has been dropping, as shown in the graph below. The drop in the murder count is statistically significant, with p = 0.014 (although part of the low murder count in 2014 is due to multiple people surviving shootings, and 2015 did see a new rise in murders).
Crime statistics for Richmond, California (data from here). Crimes marked “(R)” are measured on the right-hand scale.
The causes of Richmond’s drop in crime are difficult to elucidate, as with any single social system. The laudable community policing initiatives of the former police chief (who arrived in 2006) have been given considerable credit. The controversial Office of Neighborhood Safety has also been given credit for the drop in murders, as have initiatives by local community groups and religious leaders.
However, the steady drop in overall crime over more than a decade suggests that ordinary police work and demographic factors are also major contributors. The city has seen an influx of upper- and middle-income residents, described as the early stages of gentrification. Median incomes have risen (though poverty rates have not dropped). An influx of immigrants has seen the Hispanic population increase from 26.5% in 2000 to 39.5% in 2010 (with the Black population dropping from 36.1% to 26.6%).
In addition, the correlation matrix below suggests that there are three independent kinds of criminal activity in Richmond: (1) arson, thefts, murders, robberies, and auto thefts; (2) assaults and burglaries; and (3) rapes. The latter, disturbingly, have increased rather than decreased (and some of those rapes have been particularly horrific). In the end, Richmond can probably only be fully understood by comparing it with other cities sharing some of its characteristics – social systems are never simple. And one hopes that the drop in crime continues, so that one day Richmond will be listed among the USA’s low-crime cities.
Scientific Gems 