Math over Myth

Is Drug Prevention Worth the Price?

For nearly a decade, federal dollars have supported drug prevention programs throughout the United States. Community groups have hailed prevention--or "demand reduction"--as more effective than law enforcement efforts to shrink the drug supply. "An ounce of prevention," the cultural myth asserts, "is worth a pound of cure," and prevention advocates have argued for shifting money away from enforcement and toward prevention.

But prevention is an elusive target. How can a prevention program for adolescents today really receive blame or credit for drug use or abstention in the future, when so many other social and psychological variables intervene in the interim? The benefits of prevention (or of not doing something) also seem incalculable. Even if success can be pinpointed, how much success is necessary to make a program worth its cost? And for policymakers, how might the benefits of prevention compete with the benefits of other drug control strategies?

These questions are pertinent today. One primary goal of the 1999 national drug control strategy is "to educate and enable our youth to reject substance abuse." The federal government has begun spending $195 million a year on a new drug prevention media campaign. The national strategy also seeks, however, to balance demand and supply reduction efforts, and White House drug policy director Barry McCaffrey has called for greater accountability for all antidrug programs, which could mean boosts in funding for programs that work and cutbacks for those that don't.

To measure how well prevention can work, a RAND research team led by Jonathan Caulkins estimated the cost-effectiveness of exemplary school-based drug prevention programs and compared the estimates with those of other drug control programs. The bottom line: School-based prevention programs can be just as cost-effective as some law enforcement programs, primarily because prevention is so inexpensive. However, the real benefits of prevention are so limited that prevention could only complement--not substitute for--other antidrug strategies. Intriguingly, one strategy stands out as likely to be much more cost-effective than either prevention or enforcement, and that strategy is drug treatment.

These results apply to school-based prevention programs only. There are insufficient data available from community-based and media-based prevention programs to assess their cost-effectiveness. Furthermore, the results apply to only the best school-based programs--those few that have been proven effective by formal evaluations. The RAND research compares the best school-based prevention programs with average enforcement and treatment programs.

The Mathematics of Prevention

The researchers developed a fairly straightforward mathematical formula to calculate, dollar for dollar, how much an exemplary school-based program could reduce cocaine consumption. To give prevention its best shot, the researchers based their calculations on two successful school-based programs: Project ALERT and Life Skills Training. Both seek to inculcate in adolescents the skills to resist social pressure to use drugs.

Building on earlier evaluations of these programs, the researchers used proven reductions in marijuana use to project future reductions in cocaine use. The study focused on cocaine for two reasons: It is the country's most problematic illicit drug, and previous studies of other drug control strategies provide comparative benchmarks of cost-effectiveness for controlling cocaine. Thus, the findings of all studies can be compared with one another.

The mathematical formula contains eight factors that are multiplied together. Because of uncertainty regarding each factor, each is given a low value, a high value, and a "best-estimate" value. The table below shows the factors, the best-estimate values, the rationales behind each best estimate, and the result. Using this formula, researchers can substitute improved estimates as more information becomes available.

The tentative result shows that a model school-based prevention program will reduce future cocaine consumption by the average participating adolescent by a net present value of about 3.8 grams. Of course, most people never use cocaine, and the reduction for some could be dramatic. But the average lifetime reduction of only 3.8 grams is equivalent to what a light user would consume over three months or a heavy user would consume in about 12 days.

To determine cost-effectiveness, the reduction in use is divided by the program cost. The cost of a full program of 30 class sessions is estimated at $146.50 per student, including materials, teacher training, and the opportunity cost of using class time for nonacademic subjects. Therefore, we divide 3.8 grams by $146.50 and multiply the result by a thousand to convert grams per dollar to kilograms per million dollars. The answer: $1 million spent on prevention can reduce nationwide consumption of cocaine by 26 kilograms.

The figure below illustrates how the cost-effectiveness of model prevention programs compares with that of enforcement and treatment programs previously studied. The best estimate suggests that model school-based prevention programs can reduce cocaine consumption as much per dollar spent as some enforcement programs. The uncertainty is so great, however, that the low estimate implies that prevention is not as cost-effective as any enforcement approach, whereas the high estimate implies prevention is more cost-effective than almost all of them.

Prevention is generally competitive with enforcement despite generating small reductions in future cocaine use. As it turns out, prevention is cost-effective not because it is so effective but because it is so inexpensive. Neither prevention nor enforcement, however, appears as cost-effective as treating heavy users. Per million dollars spent, treatment can reduce cocaine consumption nationwide by a net present value of more than 100 kilograms.

The other drug control strategies represented in the figure, in order of increasing cost-effectiveness, are

eradication of coca leaf and seizures of coca base, cocaine paste, and cocaine in foreign countries
longer prison sentences (mandatory minimums) for typical cocaine dealers
interdiction of cocaine en route from source countries
conventional sentences (no mandatory minimums) for typical dealers
mandatory minimum sentences for high-level dealers prosecuted at the federal level
conventional sentences for high-level dealers prosecuted at the federal level
treatment programs effective enough to keep most heavy users off cocaine during treatment and also a small minority off heavy use after leaving treatment.

Benefits Can Easily Outweigh Costs

It is easy to demonstrate the affordability of nationwide implementation of cutting-edge school-based drug prevention programs. Putting all 3.75 million seventh graders in the United States through a program like those discussed here would cost about $550 million a year--less than 1.5 percent of current national drug control spending of $40 billion a year.

Even limited reductions in cocaine use appear to justify the costs of prevention. The researchers estimate that each dollar spent today on a model prevention program averts $2.40 in the social costs of health care, lost productivity, and crime related to cocaine abuse. Again, however, this estimate is subject to substantial uncertainty: Using the lowest and highest estimates of cost-effectiveness, the cost averted per dollar could be as low as 60 cents or as high as $5.60.

But reduced cocaine use isn't the only payoff. The researchers find that the savings from reduced cigarette-related and alcohol-related social costs, though smaller, are enough to virtually guarantee that the overall benefits exceed the overall costs. And there may be still other benefits: Strengthening the resistance skills and perceived self-efficacy of adolescents may dissuade them from associating with gangs, getting pregnant, dropping out of school, and other behaviors potentially injurious to their health or economic prospects. The researchers do not estimate the magnitude of any of these benefits.

There is another reason to fund prevention now. Drug epidemics have recurred periodically in the past, are difficult to predict, and are not always even recognized until too late--after the peak years of adolescent initiation have already passed. Because of this time lag, it would be difficult for a reactive prevention strategy to mitigate the early growth stages of an epidemic. Taking recognition and reaction lags into account, prevention programs are most effective when run about 15 years before it is even clear there is an epidemic to be prevented. How might this be done? One way might be to invest in improving the early warning signs of an epidemic. A more prudent alternative might be to run prevention programs continuously as insurance against future epidemics.

Great Uncertainties Remain

The benefits of prevention, however, are much less certain than those of enforcement or treatment. Research on enforcement and treatment programs also used low, medium, and high values to estimate cost-effectiveness. But the range of estimates for prevention ended up being two to five times as large as the ranges for enforcement and treatment.

A large part of the uncertainty about prevention stems from factors rarely considered pertinent to cost-effectiveness. For example, one might think the main benefit of prevention programs is preventing participants from initiating drug use. Decomposing the mathematical formula reveals that only 38 percent of the reduced cocaine consumption comes from these participants. Forty-four percent comes from positive spillover to friends and associates, and 17 percent comes about because reduced use by all these people shrinks the cocaine market, making enforcement against the remaining users all the more effective.

In addition, not all the reduction in quantity consumed by people in the program is the result of never initiating drug use. Some reduction is associated with reduced overall quantity consumed by those who do start using cocaine at some point. Thus, a prevention program that merely delays initiation can still decrease total consumption.

Another source of uncertainty is that drug epidemics vary over time. Had prevention programs been in place in the 1960s, about a decade before the peak in cocaine initiation, the programs might have been much more effective than in the 1990s. In the early years of an epidemic, initiation rates are higher, and so there is more potential for reduction.

Because of such uncertainties, people can reach dramatically different conclusions about the cost-effectiveness of prevention based on the same evaluations of prevention programs. There is abundant room for disagreement over the following: the indirect effects of prevention programs on nonparticipants and on enforcement, the significance of the correlation between marijuana initiation and cocaine consumption later in life, and the degree to which effectiveness declines with scale-up over the years.

Prevention as Part of the Solution

Although nationwide implementation of school-based drug prevention programs is clearly affordable, it is also clear that full-scale implementation would not eliminate or even greatly reduce the cocaine problem in the United States. Although the most exemplary prevention programs might reduce lifetime cocaine consumption by a net present value of 3.8 grams per participant, depending on the time frame considered, that figure is but a small fraction of the average lifetime consumption per capita. Clearly, most cocaine consumption will not be prevented, and the jobs of law enforcement and treatment will not be supplanted.

Furthermore, it would be years before the country could reap the benefits of prevention. Using the best estimate of effectiveness, it would take a nationwide model program 10 years to reduce the number of cocaine users by 2.5 percent. It would take 20 years to reduce the number of users by 5 percent and 40 years to achieve a 7.5 percent reduction.