From the Detroit News:
The incident was the latest in a string of homeowners opening fire to defend themselves, although after a flurry of such shootings early this year, before Monday there hadn’t been a reported incident since May 4 — an indication that criminals are thinking twice about breaking into people’s houses, Craig said.
Detroit has experienced 37 percent fewer robberies in 2014 than during the same period last year, 22 percent fewer break-ins of businesses and homes, and 30 percent fewer carjackings. Craig attributed the drop to better police work and criminals being reluctant to prey on citizens who may be carrying guns.
“Criminals are getting the message that good Detroiters are armed and will use that weapon,” said Craig, who has repeatedly said he believes armed citizens deter crime. “I don’t want to take away from the good work our investigators are doing, but I think part of the drop in crime, and robberies in particular, is because criminals are thinking twice that citizens could be armed.
“I can’t say what specific percentage is caused by this, but there’s no question in my mind it has had an effect,” Craig said.
…
A 2013 study by the American Journal of Public Health found that the states with the loosest restrictions on gun ownership had the highest gun death rates. But a 2007 Harvard University study found that banning guns would not have an effect on murder rates.
I don’t know why it says “but” instead of “and.” Those lat two conclusions are not at all mutually exclusive.