Comparing crime rates between San Francisco neighborhoods and California cities

I'm moving soon. When I realized I had to move a few months ago, I started doing research to determine the best place to move to. One thing I considered was crime. For most of the cities in the San Francisco Bay Area, I was satisfied with looking at the city-level crime statistics collected by the California Department of Justice. However, I was also considering living in San Francisco, and I didn't think it would be meaningful to compare the aggregate crime statistics for a city with a population of eight hundred and five thousand to those of much smaller cities.

So here's the question I set out to answer: How can I compare the crime rates of one neighborhood in San Francisco and those of an entire California city?

Unfortunately I couldn't find data aggregated per neighborhood. The most granular but still usable data I could get was for one San Francisco police district. Finding the data I wanted for a police district was more difficult than I would have hoped, and once I found it, understanding how it related to the city-level crime statistics collected by the California DoJ was even more work.

1. Get the data for the San Francisco police district.

For San Francisco, to get an annual report for a particular district, go here (or if the link breaks later, go to CompStat home -> Reports).

Click on the year you're interested in. For my purposes I want 2009, since that's the latest data that the state has.

Then at the bottom there are "2009 vs 2008 reports by district".
Here's the one for Ingleside.


2. Get the data for any city in California.

Go to this page to get reports for all cities in California, broken up by county.


3. Compare them.

So now how to clear up the confusing bits:
The California city-level numbers show arson separately from other property crimes, but the San Francisco district numbers include arson in the property crimes category. What I did was to add the arson number to the total property crimes number. This number is then comparable with the total property crimes number reported by the SF districts.

Also, ignore the Larceny-Theft numbers completely. Before 2011, $400 was the minimum for a theft to be considered a "grand theft". The SF districts only report grand thefts, while the per-city figures show both grand and regular thefts.

Finally, be sure to normalize by population. The SF district reports show the district's population at the top. For a California city, you can get the data from the census.

Hopefully others find this helpful.  I would not have been able to figure this out without the help of Deanne Machado from the Davis Police Department, so many thanks to her.