Access to cell phones has been credited with everything from fueling pro-democracy movements to improving market access for farmers in developing nations. Now a paper by Columbia economist Lena Edlund suggests that cell phones may have also helped slash US murder rates in the 1990s.
Edlund and coauthor Cecilia Machado ’10GSAS, an assistant professor at the Getulio Vargas Foundation in Brazil, argue that the availability of cheap cell phones in the latter half of the nineties made it easier for drug dealers and their customers to arrange handoffs in discreet locations and therefore reduced the incentive for dealers to peddle their merchandise on street corners. This eased turf battles, the researchers theorize, and reduced gang violence.
“As drug dealing became less about defending physical territory and more about accumulating customers through private networks, more dealers could enter the market and it became less profitable and there was less to fight over,” says Edlund.
As evidence, she and Machado provide county-level statistics showing that as cell-phone towers were erected across the United States, murder rates dropped in surrounding areas. Killings fell most sharply in urban neighborhoods and among Black and Hispanic men, who the researchers say are typically the victims of gang murders.
Edlund and Machado estimate that the proliferation of mobile phones may explain 19 to 29 percent of the decline in homicides between 1990 to 2000, during which time the total annual number of murders dropped from about 25,000 to 15,000. More-aggressive police tactics, stricter sentencing for drug crimes, and lower unemployment rates may also have been contributing factors.
“Our data suggest that the drop in drug-related homicides is permanent,” Edlund says. “The market for drugs has changed, and we’re not going back to the street business model.”