Studies have shown that in the New York City subways crime rates fall in the years following increased police patrols. Does this pattern suggest that the increased patrols are the cause of the crime reduction? Not necessarily; if police patrols increase following periods of unusually high crime, then the subsequent decline in crime could just be regression to the mean. Yes, a decline in crime rates would be expected to follow an increase in police patrols on the basis of the availabilly heuristic. Yes, if crime rates fall after increased police patrols, then the increased patrols must have deterred criminal activity and caused a reduction in crime. Not necessarily; the decline in crime rates is likely due to status quo bias and not increased police patrols since increased police patrols are the status quo