What Economics Can Teach Us About Criminal Justice Reform

I. What does Reform Mean

The Wikipedia page “Criminal justice reform in the United States” describes goals typical of reform advocates:

Criminal justice reform in the United States is a type of reform aimed at fixing perceived errors in the criminal justice system. Goals of such reform include decreasing the United States’ prison population and reducing prison sentences and eliminating mandatory minimum sentences for low-level drug offenders.

In other words, reformers want to change trial output. The natural questions to ask: How should we change inputs to reach the desired output? Is it better to just mandate a certain mix of output? How do courts even work? Before looking at trial output and making claims about all the ways courts can fail, we should first consider what the output of a well-functioning court would actually look like.

To paraphrase Gordon Tullock (from Trials on Trial, I think), in order to protect ourselves against theft, we can invest in heavy doors and strong locks, or in courts and police. Tullock’s point is that there are many ways to deter behavior and the legal system is only one method. We all already know that the optimal level of theft is not zero, so our investment in a legal system should be related to the costs it takes to maintain it and the benefits it confers.

Most criminal justice reformers hold specific views about the optimal reform plan – what should be illegal, what the correct sentence is for each crime, whether first time criminals should be treated differently, etc. I won’t really discuss any of that in this post, although my personal belief is that the optimal reform plan is the utility-maximizing reform plan. Today I’ll focus on the less controversial stuff. Most everyone agrees that the perfect court would have two basic features:

  • Perfect accuracy
  • Zero cost

Obviously this isn’t realistic, so a good second-best candidate is “a high level of accuracy given an acceptable level of cost.” Essentially, the marginal benefit of an additional trial should equal the marginal cost – and we should allocate resources across all crime prevention options until we reach the lowest attainable level of crime given the resources we’re willing to commit.

The most important feature seems to be that we shouldn’t be able to predict trial outcomes from traits that are uncorrelated with crimes. On the other hand, if certain traits are correlated with criminal behavior we should be able to predict trial outcomes given that information. I submit that the above is what virtually every criminal justice reformer wants.

II. Are Courts Optimal Adjudicators?

Most people will say obviously not. Reformers frequently cite federal and state incarceration statistics to argue that the legal system is plagued by institutional racism, but this is a non-answer. The legal system may well be plagued by institutional racism, but are the courts? Our legal system has two primary functions: arresting and adjudicating. How well do our adjudicating authorities adjudicate?

Using data from misdemeanor cases from the Fairfax County General District Court (FCGDC), we can begin to seriously consider that question. Before we do that, we’ll need to agree on best-case behavior for agents involved in court proceedings. Our assumptions about optimal courts suggest that adjudicators should only care about accurately determining whether a defendant is innocent or guilty. Prosecutors should be strict sentence maximizers subject to a budget constraint (to the extent that they don’t care about sentences, they are free to discriminate according to irrelevant tastes for certain defendants). Prosecutors are free to use plea bargaining as a sentence maximization tool. Defense attorneys should maximize win-rates subject to a defendant imposed budget constraint. Defendants maximize utility and are risk-averse.

What are some testable implications of these assumptions?

  1. Prosecutors allocate resources across all cases to maximize win-rates; trial time is scarce given the caseload so most cases will be resolved through plea bargaining.
  2. Prosecutors control the cases that go to trial through the use of plea bargaining such that their win-rate at trial is very high.
  3. Traits not related to guilt or innocence will not be able to predict guilt or innocence at trial.
  4. Income will be related to plea and nolle prosequi outcomes.

Implication (1) is so obvious and widely known it hardly needs to be proven. According to the New York Times, about 94% of state cases are resolved through plea bargaining.[1] According to the FCGDC data, (2) is also correct. Under 10% of cases were resolved with outcomes of “Dismissed” or “Not Guilty” – this number is roughly identical for defendants represented by public defenders or private attorneys. Initially, many people are surprised by the equality between the two attorney types; but remember, prosecutors only let cases with high win probabilities go to trial. If there is a quality difference between public defenders and private attorneys it would be seen in “Plea” and “Nolle Prosequi” outcomes. I’ll write more about the differences between public defenders and private attorneys in another post.

Implication (3), somewhat more surprisingly, is also correct. Looking only at public defenders (where all defendants are indigent so income differences across racial groups are held roughly constant) groups generally have identical outcomes (I looked at dismissals, not guiltys, nolle prosequis, guilty in absentias, and plea bargains). The exception is Hispanic defendants, who were less likely to have nolle prosequi and not guilty outcomes, but are also more likely to be guilty in absentia (Hispanics are the only group associated with guilty in absentia outcomes).

Turning to defendants with private representation, you see the appearance of racial bias throughout the data, with the notable (and predictable) exception of not guilty and dismissal outcomes. Either the courts only exhibit racial bias toward defendants who hire private attorneys, or something else is driving the outcomes. Adding a crude income control for defendants based on the median income of the town or city they live in, income has a statistically significant effect on every outcome where racial bias is apparent and no effect on not guilty or dismissal outcomes.

III. What’s Causing the Relatively High Rates of Black Incarceration?

Certainly part of the problem is the relatively low incomes associated with much of the black population in the United States. Less income means fewer inputs for trial, less ability to burn prosecutorial resources, and ultimately fewer plea bargains. But this can’t explain the entire problem. The more likely cause? The arresting authorities. In Fairfax County (and presumably many other places) blacks make up a much larger percentage of criminal defendants than you would expect. Among public defender-represented defendants, blacks make up around 39% of the total. Among defendants with private attorneys, about 23%. Blacks make up about 10% of the population of Fairfax County.

In a forthcoming post, I’ll consider the black arrest rate in greater detail, using more data from the FCGDC dataset. For now, the key thing to take away from this post is that courts themselves (at least in Fairfax County) are unlikely to be a major driver of the disparate incarceration outcomes between blacks and whites. Police behavior is a much more likely suspect.

[1] http://www.nytimes.com/2012/03/23/us/stronger-hand-for-judges-after-rulings-on-plea-deals.html?_r=0