Would a substantial reduction in the current level of enforcement activity lead to a substantial increase in the number of drug dealers? Decrease in search costs or the price of drugs? Increase in drug consumption?
To what extent does the drug market adapt to enforcement efforts by recruiting replacement dealers, finding more surreptitious ways of selling, or developing other distribution modes and routes?
There are serious obstacles to achieving even rough answers to these questions. One of the most important is that there is no statistically valid procedure in place for measuring the number of drug dealers that operate in any specified geographical area. Thus, it is not known how many dealers operate in a city or other area at any given time and, consequently, there is no reliable way of knowing whether the number of dealers has increased or decreased from one time period to another. Similarly, data on the quantity of drugs sold or consumed in a city are nonexistent, and existing data on drug prices are highly inadequate. The lack of data on the relevant outcome variables (numbers of drug dealers, search costs, prices, consumption) is a major obstacle to estimating the effectiveness of law enforcement operations against retail drug dealers.
Achieving an understanding of the effectiveness of law enforcement operations is further complicated by the many possible outcomes of such operations. Some of the consequences are consistent with the objectives of reducing the number of drug dealers and increasing search costs. For example:
The threat of arrest and incarceration may deter some individuals from becoming drug dealers, thereby reducing the number of dealers who operate in a city.
Arrest and incarceration prevent a dealer from selling drugs at least temporarily. If enough dealers are incapacitated in this way, then the total number of dealers in a city may be significantly reduced.
Other consequences tend to diminish the intended effects. For example:
Arrested drug dealers may be replaced by others. Replacement may occur through increased activity of existing dealers or by entry into the market of individuals who previously were not drug dealers.
Dealers may modify their behavior to make it less visible to police or to avoid encounters with the police. For example, drug sales operations may move from the street to indoor locations or operate as delivery ser-