Wisconsin v. Minnesota

Given the many demographic and cultural similarities between these midwestern neighbors, I’ve long been intrigued by how dramatically different the incarceration rates are in Wisconsin and Minnesota.  How is it that Wisconsin’s per capita incarceration is twice Minnesota’s?  My diligent research assistant Joe Gorndt has gathered some data to try to shed light on this problem.  First, here is the basic demographic data:


Minnesota Wisconsin
Population (2009) 5.3 mm 5.7 mm
Age under 18 24.3% 23.6%
Age over 65 12.4% 13.2%
Over 25, HS diploma 91.1% 89.0%
Bachelor degree 31.2% 25.5%
Below poverty line 10.0% 11.1%
Foreign born 5.3% 3.6%
Unemployment 5.8% 6.1%

Not much to distinguish the states here.  The most notable difference seems to be the higher percentage of adults with college degrees in Minnesota, but this is hardly a dramatic difference and doesn’t seem likely to explain the imprisonment disparity.

Now take a look at the crime and criminal-justice statistics, courtesy of the National Institute of Corrections.


Minnesota Wisconsin
Prison population 9986 21110
Parole population 5081 18105
Probation population 127627 50418
Crime rate 3.11% 3.03%
Violent crime 0.26% 0.27%
Property crime 2.85% 2.76%
Incarceration rate 0.19% 0.37%
Cost/inmate $32,573.00 $31,806.00

Crime rates are incidents/population in 2008.

What is striking here, besides the imprisonment disparity, is an even more marked disparity in the probation population going the other direction.  In fact, it turns out that Minnesota has far more total people under criminal-justice supervision than Wisconsin.  The difference is that Minnesota keeps its offenders in the community, while Wisconsin sends its offenders to prison.  Interestingly, it does not appear that these tendencies result in materially higher crime rates in Minnesota; in fact, Minnesota’s violent crime rate is slightly below Wisconsin’s.

One question that I was particularly interested in exploring was whether Minnesota’s admirable sentencing guidelines should get the credit for the state’s relatively low incarceration rate.  There might be something to this, although there seems to be more going on than just the guidelines.  The guidelines went into effect in 1980.  The table below indicates the prison population of each state from 1977 through 1996.  As you can see, there was a marked disparity between the two states even before the guidelines.  However, the disparity became even greater in the guidelines period.  Both states saw their prison populations explode in the 1980’s and 1990’s, but Wisconsin’s grew at an even faster rate than Minnesota’s.  Minnesota’s population nearly tripled, but Wisconsin’s nearly quadrupled.  It is possible that the guidelines helped to restrain the Minnesota growth.

  Minnesota Wisconsin MN/WI
1977 1755 3347 0.52
1978 1837 3432 0.54
1979 1984 3677 0.54
1980 1884 3788 0.5
1981 1909 4249 0.45
1982 2149 4441 0.48
1983 2235 4226 0.53
1984 2331 4845 0.48
1985 2495 5243 0.48
1986 2515 5554 0.45
1987 2706 5847 0.46
1988 2942 6159 0.48
1989 3140 6669 0.47
1990 3215 7247 0.44
1991 3516 7686 0.46
1992 3849 8191 0.47
1993 4060 8781 0.46
1994 4372 10022 0.44
1995 4628 11199 0.41
1996 4804 12530 0.38

Look for more posts here in the future trying to make sense of the Wisconsin-Minnesota imprisonment puzzle.