Assumptions image
Example 1:
A working group of criminal justice professionals assembled as part of the now well-known Boston Gun Project came to the table with the assumption that illegal guns were being smuggled into Massachusetts from southern states with more lax gun laws. While these outside states were certainly responsible for some of the crime guns used by juveniles in Massachusetts, analysis showed that "one-third of the traceable guns recovered from youths in the past 5 years had been purchased originally in Massachusetts... this local market had been almost entirely ignored by law enforcement."1
Example 2:
Another working group of criminal justice professionals assembled as part of a project to take on the gang problem in East Los Angeles came to the table with the assumption that conflict over drug-dealing was primarily responsible for most of the gang homicides in the area. Analysis showed that relatively few of the homicides were motivated by fighting over drug markets, even though many of the victims and offenders were regular users or dealers. This finding has been replicated in several other cities.2

These are just two examples meant to highlight the vital point that challenging assumptions is a useful exercise. A skillfully conducted analysis is able to provide key insights that sometimes challenge existing assumptions and sometimes confirm them. And as these examples show, analysis, when done right, is highly practical and relevant.


1 Kennedy, David M. (1997). Juvenile Gun Violence and Gun Markets in Boston. NIJ Research Preview. Washington, DC: National Institute of Justice.
2 Tita, George, K. Jack Riley, Greg Ridgeway, Clifford Grammich, Allan F. Abrahamse, and Peter W. Greenwood (2003). Reducing Gun Violence: Results from an Intervention in East Los Angeles. Santa Monica, CA: Rand.