Prison Crowding Over Time: The Relationship of Density and Changes in Density to Infraction Rates

The relationship between institutional density (population divided by capacity) and institutional infractions (both violent and nonviolent) was examined for 65 different institutions (25 state prisons, 33 county prisons, and 7 transitional centers) by month over a 10-year period. Across all institutions, there appeared to be no consistent pattern of effects for density. Even within institutions, there was no consistent pattern across time. Multivariate analyses holding other factors constant indicated that institutional density and rate of change of prison populations had statistically significant effects on both types of infractions, although the size of the effects was very small. Additional analyses indicated that these effects were particularly true for prisons for youth. Overall, the results indicated that institutional factors other than density were the strongest predictors of infractions.