Peaceable kingdoms and war zones: Pre-emption, ballistics and murder in Newark

Between 2000 and 2006 the murder rate in Newark doubled while the national rate remained essentially constant. Newark now has eight times as many murders per capita than the nation as a whole. Furthermore, the increase in murders came about through an increase in lethality: total gun discharges rose much more slowly than the likelihood of death per shooting. In order to explain these trends we develop a theoretical model of murder in which preemptive killing and weapon choice play a central role. Strategic complementarity amplifies changes in fundamentals, so areas with high murder rates (war zones) respond much more strongly to changes in fundamentals than those with low murder rates (peaceable kingdoms). In Newark, the changes in fundamentals that set off the spiral were a collapsing arrest rate (and probably a falling conviction rate), a reduction in prisoners, and a shrinking police force