Alcohol consumption and crime
Consistent with our common wisdom (and occasional first-hand experiences), findings from laboratory experiments indicate that excessive alcohol consumption can increase aggressiveness and emotional responses, and inhibits decision-making skills.
It is then possible that excessive alcohol consumption can have an important consequence on one’s likelihood of criminal offending and victimization.
Indeed, survey responses from U.S. prisoners show that 33 percent were under the influence of alcohol at the time of offense. 47 percent of prison and jail inmates report that they were dependent on or abused alcohol. According to the 2005 National Crime Victimization Survey, 21 percent of victims of violent crime reported that the perpetrator was drunk at the time of offense. (The actual share of alcohol use by criminals is likely to be higher, as 44 percent of the victims reported they “did not know” whether offenders were drunk or not at the time of offense.) Drinking can also increase the probability of victimization, as alcohol-induced impairment makes the drinker an easy crime target.
But how can we test whether alcohol consumption increases crime or not? As always, a simple correlation between drinking and crime does not give us the causal effect of drinking on crime, because people’s decision to drink and to commit crime can be correlated with other crime-relevant factors. For example, if binge drinkers are more reckless and risk-loving than their sober counterparts on average, the difference in their offending rates may be driven by their personality difference, not by their alcohol consumption patterns.
Beer Taxes and Minimum Legal Drinking Age
One popular remedy to this problem has been to exploit changes in the level of alcohol consumption caused by government taxes. For example, when government raises taxes on alcoholic beverages, this price increase should result in lower alcohol consumption (basic economics here). Meanwhile, a government decision to increase alcohol tax usually has little to do with crime rates and other crime-relevant factors, and applies to all consumers, regardless of their crime-relevant characteristics.
A number of studies show that higher excise tax on alcohol reduces alcohol consumption and lowers crime. Economists Philip Cook and Michael Moore analyzed data on crime rates, beer taxes and prices across U.S. states between 1979 and 1987, and found that higher beer taxes were followed by fewer rapes and robberies. Jeffrey DeSimone extended Cook and Moore’s analysis by using alcohol price data between 1981 and 1995, and found that beer taxes led to fewer assaults, larcenies, motor vehicle thefts as well.
Alternatively, some researchers used the minimum age requirement for drinking as an identifying variation to recover the causal effect of alcohol consumption on crime. The regression discontinuity analysis we saw last week is particularly useful here. First, think about a hypothetical randomized experiment. I would randomly assign research participants into two groups, allow one group to consume alcoholic beverages and prevent the other group from consuming any. I will then compare the offending rates of the two groups, and take the difference as the causal effect of alcohol consumption on crime. However, aside from the obvious ethical concerns of forcing some people to drink and others to abstain, it would require tremendous costs and efforts for me to monitor and enforce the assigned drinking behavior from the research participants. Accurately monitoring their subsequent criminal behaviors will not be any easier.
The minimum legal drinking age provides an ideal empirical setting which closely resembles this hypothetical experiment. American youths below age 21 are prohibited from drinking, but as soon as they turn 21, they can legally buy and consume alcoholic beverages from any bars and liquor stores. Surely, some underage people consume alcohol illegally, but law enforcement agencies actively enforce the minimum age requirement and punish violators. (This means that researchers don’t have to spend any effort on monitoring and enforcing the assigned drinking behaviors. Police officers are already doing it for them.) Moreover, except for the legal eligibility to drink, there should be minimal difference, in terms of health conditions, education attainment, employment patterns, etc., between individuals just below and above age 21. Thus, any difference in crime participation between individuals just below age 21 and just above age 21 can be plausibly viewed as the causal effect of increased alcohol consumption.
Analyzing a large-scale health interview survey and official arrest data from California, economists Christopher Carpenter and Carlos Dobkin found that the rate of alcohol consumption jumps by 30 percent on average when people turn 21. Further, they found that arrest rates for assault, robbery, DUI, and nuisance crimes (including drunkenness and disorderly conducts) sharply increase at the age 21 cutoff as well. The increase amounts to 63 more assault arrests and 8 more robbery arrests per 100,000 persons.
Together, these findings present convincing evidence that increased alcohol consumption by young adults is criminogenic. Carpenter and Dobkin also used the same data to examine the causal effect of drinking on mortality and non-fatal injuries. The results show that individuals just above the minimum legal drinking age are also more likely to visit emergency departments and die from suicide, motor vehicle accident and alcohol poisoning.
A well designed and implemented regression discontinuity analysis has strong internal validity (i.e., its finding can be credibly viewed as the causal effect of interest under the specifics of the given research setting), but its external validity may be more questionable. Do you see how Carpernter and Dobkin’s finding may not be easily generalized to other segments of the population?
- Carpenter, Christopher, and Carlos Dobkin. “The Minimum Legal Drinking Age and Public Health.” Journal of Economic Perspectives 25.2 (2011): 133-156.
- Cook, Philip J., and Michael J. Moore. “Drinking and Schooling.” Journal of Health Economics 12.4 (1993): 411-429.
- DeSimone, Jeff. “The Effect of Cocaine Prices on Crime.” Economic Inquiry 39.4 (2001): 627-643.
© Songman Kang, Hanyang University