The researchers plotted the locations of drug treatment centers in Baltimore as well as those of corner stores, convenience stores and liquor stores with seven-day, on-premises/off premises licenses. (Of note, there are more than eight times as many of that kind of liquor store as there are drug treatment centers.) They then used statistical methods to control for the socio-economics of the neighborhoods in which the business are located and to calculate the incidence of violent crime in proximity to each type of establishment, and the degree to which such crime tapered off as the distance from them decreased. The results: Violent crime was about one and a half times more prevalent around liquor stores and corner stores than it was around drug treatment centers or convenience stores. Furthermore, violence dropped more sharply the farther one traveled from liquor or corner stores than it did in the case of drug treatment centers, suggesting they aren't magnets for crime at all but merely tend to be located in places where crime is already high. Indeed, the researchers found that the majority of drug treatment centers were in the most disadvantaged areas of the city, whereas only a fifth of liquor stores were.