'Broken windows theory'

Based on an article titled Broken Windows by James Q. Wilson and George L. Kelling, which appeared in the March 1982 edition of The Atlantic Monthly. The title comes from the following example:

"Consider a building with a few broken windows. If the windows are not repaired, the tendency is for vandals to break a few more windows. Eventually, they may even break into the building, and if it's unoccupied, perhaps become squatters or light fires inside.
Or consider a sidewalk. Some litter accumulates. Soon, more litter accumulates. Eventually, people even start leaving bags of trash from take-out restaurants there or breaking into cars."

A successful strategy for preventing vandalism, say the authors, is to fix the problems when they are small. Repair the broken windows within a short time, say, a day or a week, and the tendency is that vandals are much less likely to break more windows or do further damage. Clean up the sidewalk every day, and the tendency is for litter not to accumulate (or for the rate of littering to be much less). Problems do not escalate and thus respectable residents do not flee a neighborhood.

The theory thus makes two major claims: that further petty crime and low-level anti-social behavior will be deterred, and that major crime will, as a result, be prevented. Criticism of the theory has tended to focus only on the latter claim.

The theory in action

The book's author, George L. Kelling, was hired as a consultant to the New York City Transit Authority in 1985, and robust measures to test the Broken Windows theory were implemented by David Gunn. Graffiti vandalism was intensively targeted, and the system was cleaned line by line and car by car from 1984 until 1990. Kelling has also been hired as a consultant to the LAPD and to the Boston Police Department.

In 1990 William J. Bratton became head of the Transit Police. Bratton described George L. Kelling as his "intellectual mentor", and implemented zero tolerance of fare-dodging, easier arrestee processing methods and background checks on all those arrested. Republican Mayor Rudy Giuliani also adopted the strategy more widely in New York City, from his election in 1993, under the rubrics of 'zero tolerance' and 'quality of life'.

Thus, Giuliani's "zero tolerance" roll out was part of an interlocking set of wider reforms, crucial parts of which had been underway since 1985. Giuliani had the police even more strictly enforce the law against subway fare evasion, and stopped public drinkers, urinators, and the "squeegee men" who had been wiping windshields of stopped cars and demanding payment. Rates of both petty and serious crime fell suddenly and significantly, and continued to drop for the following ten years.

Critics of the theory

Critics point to the fact that rates of major crimes also dropped in many other US cities during the 1990s, both those that had adopted 'zero tolerance' policies and those that had not.

Other research has pointed out that the 'zero tolerance' effect on serious crime is difficult to disentangle from other initiatives happening at around the same time in New York. These initiatives were 1) the police reforms described above, 2) programs that moved over 500,000 people into jobs from welfare at a time of economic buoyancy, and 3) housing vouchers that enabled poor families to move to better neighborhoods.

Alternative explanations that have been put forward include:

Among academics, David Thacher (Assistant Professor of Public Policy & Urban Planning at the University of Michigan) stated in a 2004 paper that:

"...social science has not been kind to the broken windows theory. A number of scholars reanalyzed the initial studies that appeared to support it ... Others pressed forward with new, more sophisticated studies of the relationship between disorder and crime. The most prominent among them concluded that the relationship between disorder and serious crime is modest, and even that relationship is largely an artifact of more fundamental social forces."

Thacher goes on to state that: "These challenges to the broken windows theory have not yet discredited order maintenance policing with policymakers or the public."

In the best-seller Freakonomics (Willam Morrow, 2005;  economist Steven D. Levitt and co-author Stephen J. Dubner cast doubt on the notion that the Broken Windows theory was wholly responsible for New York's drop in crime. He instead noticed that years before the 1990s, abortion was legalized. Women who were least able to raise kids (the poor, addicts and unstable) were able to get abortions, so the amount of children being born in broken families was decreasing. Most crimes committed in New York are committed by 16-24 old males; when this demographic decreased in number the crime rate followed.