When a substance abuse treatment centre opens, does that decrease local crime, or increase it? Theory doesn't help us much here, because you can argue theoretically in both directions. On the one hand, a treatment facility reduces drug use, so may reduce drug-induced aggressive behaviour, reduce crimes by drug users looking to earn money to fuel their habits, and reduce violence between drug dealers. On the other hand, a facility attracts drug users to collect in an area, and changes the types of people and places they interact with, all of which might increase crime (concentrated in areas around the facility) - at least, that's the NIMBY argument against substance abuse treatment centres. Due to the theoretical ambiguity, we need to answer the question of the relationship between substance abuse treatment centres and crimes empirically.
That's what this 2018 article by Samuel Bondurant, Jason Lindo (both Texas A&M University), and Isaac Swensen (Montana State University), published in the Journal of Urban Economics (ungated earlier version here), does. They use annual county-level data on the location of substance abuse treatment centres from the US Census Bureau's County Business Patterns, and crime data from the FBI's Uniform Crime Reports, and from the National Center for Health Statistics' Multiple Cause of Death database. They find that:
...county-level homicide rates are reduced by SAT facilities. Specifically, the estimates indicate a 0.25% decline in intentional homicide death rates associated with an additional SAT facility...
...the point estimate for the effect on sexual assault is also negative, suggesting that SAT facilities reduce sexual assault as well, it is not close to being statistically significant at conventional levels. The estimated effect on aggravated assaults also suggests a reduction in crime associated with SAT facilities, though this estimate is only marginally statistically significant...
The point estimates indicate that a SAT facility reduces robbery by 0.11%, motor vehicle theft by 0.12%, burglary by 0.05%, and larceny by 0.06%. The estimated effects larceny are not statistically significant at conventional levels.
In other words, substance abuse treatment centres are associated with lower crime rates. Interestingly though, in the Discussion section of their article, Bondurant et al. weigh up the costs and benefits of these facilities:
...these calculations suggest that the county-level benefits of an additional facility - in terms of drug-related mortality and criminal activity - are between 5.4 and 7.65 million dollars, depending on whether effects on homicides are included. Reductions in crime account for approximately 20-40% of these benefits...
A back-of-the-envelope calculation indicates that the annual costs of treatment for a SAT facility are approximately 1.1 million dollars... These calculations suggest that the benefits of expanding treatment facilities far outweigh the associated treatment costs.
Bondurant et al. argue that their results demonstrate causal effects, because the effects occur only after a change in the number of facilities, and not before (they establish this by looking at lead and lag variables of the number of facilities). I don't find those results convincing enough to believe that the results overall are causal. Also, one bit I found interesting in this research is that they use the number of facilities in the prior year as their explanatory variable. This is explained later in the paper as:
...a choice we made to avoid attenuation bias that would likely be caused by the fact that newly opened (or closed) facilities would only affect counties for some fraction of the year.
This attenuation bias is likely to be a problem in a lot of the literature that looks at the relationship between facilities of various types (like alcohol outlets, marijuana dispensaries, or treatment centres) and crime (or other measures of harm). That includes my own work on the relationship between alcohol outlets and measures of harm (e.g. see here). The number of facilities is measured at one point in time, but the events (crimes, etc.) occur over a period of time that might be before or after the number of facilities has changed. This leads to measurement error in the number of facilities, and measurement error leads to attenuation bias, where the statistical model underestimates the size of the relationship between the number of facilities and crime. This problem is likely to be greatest for annual data (and, in contrast, would likely not be much of a problem at all for daily data).
The choice of using the number of facilities from the year before is an interesting solution, but I think it still creates measurement error, only the measurement error is in the opposite direction to what would happen in the case of most research of this type. When a new facility opens during a year, the standard approach assumes that facility is open for the whole year, overstating the number of facilities. In Bondurant et al.'s analysis, it effectively assumes that facility is closed for the whole year, understating the number of facilities. So, there is still measurement error.
Despite the lack of explicit causal analysis, the cost-benefit analysis is reasonably convincing (to me, at least). The benefits of substance abuse treatment centres outweigh the costs (in the US), and there should be more of them.
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