That doesn't really work. It's impossible to restore individual justice by using statistical numbers as KPI. How'd you know the system became "fair"? By comparing the racial ratio of incarceration to the ratio in the general population? That doesn't make any sense if you account for disproportionate representation of black people on the lower end of income scale, which is generally associated with violent crime and reoffending. What target level of disproportionate incarceration of blacks would you target? Or would you prefer giving white people harsher sentences just for the colour of their skin? Statistics may point to problems (so we do investigate why exactly black people are more likely to get in prison), but simple ratios aren't nearly enough to bring justice.