The District of Columbia Crime Policy Institute released an intriguing brief this morning which claims that a small number of Census blocks in the District account for a large amount of the city’s crime. [Full disclosure: I used to be employed at the Urban Institute, which houses DCPI.] According to the two-page brief:

Most crime is concentrated in a relatively small number of blocks in the District—in any given year, more than one-quarter of the crimes occur in just five percent of the blocks. And the approximately 20 percent of blocks in the District that fall into the ‘high crime’ categories (with 10 or more crimes per year) account for more than 60 percent of the crime that occurs in the District. In addition, while not shown in the table, over 40 percent of blocks in the high crime categories were zoned largely for commercial activity.

On the map accompanying the brief (which is embedded after the jump, or you can download a PDF here), several of the areas where the most crimes occur will be no big surprise to those who have lived in the city for some time — for instance, the dense, centralized Third Police District contains several high-crime blocks. But there are also some surprising spots where high amounts of crime are reported, like a blip on upper Connecticut Avenue in Chevy Chase.

The figures represent reported Part I crimes (homicide, sexual assault, aggravated assault, robbery, burglary, larceny, motor vehicle theft, and theft from a motor vehicle) and map by Census blocks, not typical city blocks. A Census block is the smallest unit measured by the U.S. Census Bureau — and occasionally they can be rather large, which helps explains why certain areas, like the larger blocks around American University and some of the blocks in the Seventh Police District, are designated as high-crime areas. DCPI researchers also confirmed with us that the presence of college campuses also plays a role in the designation of high-crime areas, like ones located around Georgetown University.

On the bright side, the brief also notes that, on average, nearly a quarter of all D.C. census blocks have experienced no crime over the last decade while a majority have experienced four or fewer crimes per year.