The graph is somewhat interesting, a bunch of squiggles. But the
conclusions drawn by the study are really something else.
In a nutshell, two decades ago, welfare payments were switched from checks to debit cards. No checks meant that there were no checks to cash, so there were fewer people walking around with wads of cash, so robberies went down. This study says that a whopping 10% reduction in crime nationally is directly attributable to the switch from welfare checks to welfare debit cards.
Previous explanations thrown out there for the crime reduction were the elimination of lead from gasoline and paint, and an increase in police and prison spending. But those things didn't correspond anywhere near as closely to the reductions in crime as the timing of this welfare payment switch does.
The only one that jumps out to me as being questionable is Larceny. It also went down, but it had been going down steeply already and its rate of decent seemed to be thwarted by the welfare payment switch.
