Chris! I spent my whole walk to work this morning thinking about the question of whether restoring voting rights would decrease the likelihood of an ex-felon returning to crime after being released. This, despite not actually reading your paper, and despite not knowing anything about the larger literature in the area. And now, despite all this ignorance, I'm going to write a long post about it!
Readers who are not Chris should keep in mind, I have had two separate institutional occasions to familiarize myself with the Uggen oeuvre, and I have enormous respect for the work he's done and what he's trying to do. I'm sure he's thought about most/all the same issues as I have and in more depth to boot. So this isn't a directed criticism at him or at others at all. Indeed, in writing down my thoughts, I considered changing the example to something entirely different just to make plain that I wasn't pretending to offer informed commentary on the work of Chris and others in this area, but then I decided not to, partly because this rumination has already taken up enough of my morning.
Instead, as is usual for this blog, it's All About Me. Specifically, it's about me thinking through why I am such a causal pessimist. So, allow me a morning stroll through how I think about things in terms of imagining the question of whether voting rights reduce recidivism in stylized terms mostly innocent of knowledge of the actually available data and evidence.
Consider: Frankie and Johnny are both ex-felons. In terms of the measures we have on them, Frankie and Johnny are identical. Frankie votes, Johnny doesn't. A year later, Frankie hasn't had any further trouble with the law, while Johnny knocked over a liquor store and is back in jail. If Johnny had voted instead of Frankie, would their positions be reversed?
Aggregate to: Frankie and Johnny are just two members of a large sample of ex-felons. In the whole sample, though, everybody can be divided into pairs like Frankie and Johnny, where they are alike on all other pre-election-day measures, except that the Frankies voted and the Johnnies did not. A year later, 20% of the Frankies are back in jail, as opposed to 30% of the Johnnies. If the Johnnies had voted and the Frankies had not, would these percentages be reversed? (Or, more fairly, if the Johnnies had the reintegrative experience manifested in voted and the Frankies had not, would the percentages be reversed?)
In a nutshell: the whole inference that there is something causal about voting turns on the idea that Frankie and Johnny really were otherwise alike, just that one voted and the other didn't. (If you know from the start that the Frankies and Johnnies are different, we can engage in strategies of "covariance adjustment" to attempt to account for these differences, but this results in an even weaker inference than the hypothetical matched-pairs scenario, so if you are already a causal pessimist in the matched-pairs scenario, you are necessarily even more of a pessimist when covariance adjustment is required.)
The problem: If they were so alike, why did Frankie vote and Johnny not? I mean, isn't Frankie practically screaming, "Yo! Don't treat me like I'm identical to Johnny! He spent election day watching TV, and I went out and voted!" Fundamentally, it doesn't matter how many different ways (as manifested in variables) that you have showing how Frankie and Johnny are alike. Perversely even, to some extent, more measures can be misleading, to whatever extent they can foster the illusion that Frankie and Johnny really were alike, except that one voted and the other didn't. So long as the decision to vote is highly nonrandom and says something about the person who chooses to vote, Frankie and Johnny are revealing an important difference between the two of them by the very fact that one voted and the other didn't.
A digression: In a different-but-analogous scenario, this is the closest I've come to lapsing into profanity in my graduate methods class. We were looking at a paper on neighborhood effects, where the whole inference turned on the idea that two kids entering junior high were otherwise identical (or adjustedly identical), except that one lived in a bad neighboorhood and the other lived in a good neighborhood. To which I said, animatedly, "If they are so freaking alike, why do they live in different neighborhoods?" And then, even more loudly and slowly: "If they are so freaking alike, why do they live in different neighborhoods?"
The situation would be more promising if: You had two groups of Frankies and Johnnies who were otherwise identical, and the Frankies could vote and the Johnnies couldn't. If you have reason to think the Johnnies would have voted in the same proportion if only they could vote--which, if they were really otherwise identical, they would--then a lower recidivism rate for the Frankies vs. the Johnnies is possibly compelling. (It depends on how well one can make the "otherwise identical" case, especially since, for example, if the Frankies live in one state and the Johnnies live in another, you have to start worrying about the ways in which the state affects their probability of re-imprisonment, etc., etc.)
Barring that, the situation is not so bleak if: You had two groups of Frankies and Johnnies who were otherwise identical, except the Frankies happened to be in a circumstance that exerted an effect on their probability of voting (or, really, their average level of electoral-related civic integration) without at all affecting their probability of recidivism. And so, the Hunt For Exogenous Variation is on. Say the Frankies were released in the year preceding various presidential elections, and the Johnnies were released in the year after various presidential elections. It might be compelling to see that the Frankies had lower recidivism rates than the Johnnies. (One problem here is that elections are also known affect the probability of recidivism, as when mayors increase policing in their own election years to appeal to crime-antsy voters.)
Additionally, there may be the opportunity to Disaggregate And Conquer: Frankies and Johnnies are otherwise identical. Imagine that there are Class A felonies and Class B felonies. Frankies can only vote if they have committed a Class A felony, not if they've committed a Class B felony. Johnnies cannot vote regardless. We compare the recidivism rates for Class A and Class B felons. Whatever the relative difference in recidivism rates for Class A felons vs. Class B felons among the Johnnies, the relative rate among the Frankies should be even lower. In other words, if recidivism rates were 30% for both Class A and Class B felons among the Johnnies, then we might be persuaded that voting matters if the rates among the Frankies were 20% for the Class A felons and 30% for the Class B felons.
And, all the while, the question has actually shifted: The larger animating question for policy is, "Does restoring voting rights to felons affect the recidivism rate?" That question depends actually on comparisons across states, so instead of Frankie and Johnny you have Frankansas and Johnnisota. You can imagine how hard that is, i.e., "If the two states are so freaking alike, why does one allow ex-felons to vote and the other doesn't?" So you pretty much have to change the question. The story of Frankie and Johnny begins with the mutation of the question to something like: "Does voting reduce the probability of recidivism?" or perhaps more elaborately "Does the sense of civic reintegration made possible by and manifested essentially in the act of voting reduce the probability of recidivism?" But it could be that restoring the voting rights to felons decreases recidivism by decreasing stigma or increasing reintegration regardless of whether ex-felons take advantage of the franchise by actually voting. This is especially scary because we could get results that show that voting doesn't matter for recidivism when restoring the right to vote (the real matter of policy) does matter. In other words, problems of causal inference can force us into addressing causal questions that are different from the ultimate questions of policy interest, and the questions can have discrepant answers.
A final irony of all this being: For my own beliefs about whether ex-felons should be allowed to vote, the answer to the question about recidivism doesn't matter on way or the other. I would probably even support restoring the right to vote to ex-felons if it increased their probability of recidivism. But, of course, there are people out there who might be persuaded to agree with the policy change if it was shown that restoring voting rights reduced recidivism rates. And what I ultimately care about is the policy change, not whether the reason the policy change gets enacted coincides with my own beliefs about the reasons the policy change is desirable. So I'm invested in the answer even though it's irrelevant to my own position.