A 1985 Department of Justice survey of incarcerated felons reported that 57 percent of the felons polled agreed that "criminals are more worried about meeting an armed victim than they are about running into the police."
Researcher Gary Kleck found that 92 percent of criminal attacks are deterred when a gun is merely shown (or, rarely, a warning shot fired). By inference, this means that open carry would have the effect of deterring crime in the same way that a thief might choose another restaurant when he sees police eating at his intended target.
http://www.usnews.com/debate-club/should-people-be-allowed-to-carry-guns-openly/open-carry-deters-crime
