This forecasting tool is based on an analysis of the main factors correlated with—and believed to be influencing—Illinois crime trends in the past four decades.

The figures underneath each slider and next to the violent and property crime bars are recent values for these factors and for the rates of violent and property crimes (crimes/100,000 Illinois residents). These provide a baseline for exploring the predicted effect on crime rates of an increase or decrease in any of those factors.

In the statistical analysis on which this tool is based, numerous factors were found to be predictors of each year's rate of violent crime, property crime, or both. For violent crime, the factors were the change over the previous two years in the rates of inflation and teen births, in the fraction of the population with a bachelor’s or higher degree, and in several factors related to the number of people under criminal-justice supervision. For property crime, the predictors included changes over the previous two years in the same criminal-justice variables and in the teen birth and inflation rates, as well as in the percentage of adults who are divorced, percentage of the population between ages 15 and 24, and the percentage of housing units in the state that are vacant.

The weight of each factor—the size of its effect on crime—varied considerably, as will be evident from altering them. The factors also differ in that some, such as the imprisonment rate, are susceptible to direct change through policy whereas others, such as the size of the 15-24 segment, are not.

Teen Births = births/1,000 females age 15-24
Divorce = % divorced
Inflation = U.S. inflation rate
15-24 = % of population age 15-24
Education = % of population with bachelor's or higher
Imprisonment, Parole, Probation, Jail = persons/100,000 population
Length of Stay = average prison stay in months
Vacancy = % of housing units vacant