Emails, Alfred Blumstein, J. Erik Jonsson University Professor of Urban Systems and Operations Research, Carnegie Mellon University, Sept. 24 and 29, 2015
Sept. 24, 2015
Is there any way you know of that 15 percent of the population commits all crimes – or, perhaps, all violent crimes?
I don't know the source for the 15% number, but given the large number of people who get arrested, it's hard to believe that they account for a full 100% of all crime.
On 9/29/2015 6:47 PM, Selby, Gardner (CMG-Austin) wrote:
Sorry to bug you again. But just today, I fielded the official’s explanation for his claim 15 percent of the population commits 100 percent of the crimes. I am pasting it below. I am interested in your analysis; does it stand up?
The Lt Governor uses 15% as the number of citizens that commit 100% of crime as an indicator of the number of criminals in the total population to make the point that most citizens are law abiding. That is higher than statistics would indicate. According to law enforcement data we have approximately 2.2 million people in jail in America and another 5 million on probation and parole. That is roughly 2.5% of the total population that has been convicted of a crime including non-violent drug offenses.
Sept. 29, 2015
Lots of people do crime but never get arrested. Also, lots of people get arrested but never get incarcerated. It sounds like he wants to use the incarcerated population as the "people who do crime", but that 2.5% is much lower than his 15%. Thus, I have no sense of where his 15% comes from, what it is intended to represent, or how it was estimated.
Good luck in pinning it down if you must.
Carnegie Mellon University