The 'Broken Window' theory bolstered, yet still inconclusive

LA Times - Graffiti study bolsters 'broken window' theory
and
WTOP.com (AP) - Study shows messiness leads to behavior decline
then see
University of Chicago Chronicle - Study authors find cracks in 'broken-windows'
and
Boston Globe - The cracks in 'broken windows'

The broken window theory (put forth in 1982 by George Kelling and James Wilson) is that a neighborhood's environmental factors of orderliness, cleanliness and respect for the small things like graffiti, littering and other minor infractions will reduce the likelihood of larger crimes being committed there. NYC is credited with adopting this policy in the 90s and reducing violent crime by 50%. The study in the Netherlands placed flyers on bicycles with no trash can around. When a nearby wall was clean, people littered the flyers 30% of the time, when it was covered with graffiti, littering was at 69%. Relatedly, people doubled their rate of pilfering a small amount of money sitcking out of a mailbox when it was surrounded with trash vs when it wasn't: 25-27% to 13%. The theory is that when perceived social pressures to behave are lower, people act on their other 'instincts', maximization of resources and immediate gratification. Second article lists some of the other experiments the study conducted.

The third article shows the dissenting opinion of Bernard Harcourt: that the policing of cleanliness and orderliness may reduce petty crime, but there is no evidence that violent crime is reduced because petty crime is. Authors attribute NYC's drop in crime not to broken-window policing but instead the he crack-cocaine epidemic and the violence and serious crime surrounding it: once the epidemic receded was when NYC saw its biggest reduction in violent crime.

The Globe article traces the influence of these policing methods from William Bratton in Boston-- who in the early 1980s believed that patrolmen shouldn't just respond to calls but rather keep order in the community and deal with 'quality of life' issues-- to Rudy Guiliani's rise to NYC mayor and eventual hiring of Bratton. Other studies like ones done by sociologist Robert Sampson predict that perceptions of disorder is fueled by racial demographics, specifically the number of blacks and latinos in a neighborhood. Sampson and his colleague Stephen Raudenbush are longtime critics of Kelling.