The concept of broken window theory was introduced by James Q. Wilson and George L. Kelling in their Atlantic magazine article Broken Windows. The authors argued that visible signs of neglect change the perception about an environment and lead to more neglect and over time worsening conditions:

Social psychologists and police officers tend to agree that if a window in a building is broken and is left unrepaired, all the rest of the windows will soon be broken. This is as true in nice neighborhoods as in rundown ones. Window-breaking does not necessarily occur on a large scale because some areas are inhabited by determined window-breakers whereas others are populated by window-lovers; rather, one unrepaired broken window is a signal that no one cares, and so breaking more windows costs nothing.

[. . .]

We suggest that “untended” behavior also leads to the breakdown of community controls. A stable neighborhood of families who care for their homes, mind each other’s children, and confidently frown on unwanted intruders can change, in a few years or even a few months, to an inhospitable and frightening jungle. A piece of property is abandoned, weeds grow up, a window is smashed. Adults stop scolding rowdy children; the children, emboldened, become more rowdy. Families move out, unattached adults move in. Teenagers gather in front of the corner store. The merchant asks them to move; they refuse. Fights occur. Litter accumulates. People start drinking in front of the grocery; in time, an inebriate slumps to the sidewalk and is allowed to sleep it off. Pedestrians are approached by panhandlers.

[. . .]

To be sure, slippery slopes are not inevitabilities. That said, the authors made their point effectively at the time. The article became well-cited and broken window theory has clearly impacted, how police departments around the country thought about policy and implemented policing over the decades.

Broken windows in black & white of a disused power station.
Broken windows in black & white of a disused power station. by Mark Westguard is licensed under CC-CC0 1.0

This has not universally been received well and it has been questioned since. Over the years, both the original message as well as some of its interpretations have at times been criticized as simplified. Where it resulted in policy or specific programs, criticism has focused on factors such as bias against marginalized groups, socioeconomic status, et cetera.

I am not a social scientist nor a criminologist or public policy expert. This is not about that, not specifically. When I first learned about broken window theory, it was in a completely different context.

Software Engineering

The Pragmatic Programmer, by David Thomas and Andrew Hunt is one of my favorite books about software development. In an early chapter on software entropy, the authors introduce broken windows into the discussion.

As software is evolved over time, the risk for disorder is ever present. Although they do not manifest physically, quality issues in software are a critical concern for the people, who care about sustainably continuing the development of that software. Trouble seems to invite more trouble — people have to care.

I happen to have two paper copies of that book at home – one of the first edition from 1999, as well as a copy of the 20th anniversary edition from 2019. Both editions include that chapter and cover the topic. However, whereas the former discusses briefly how broken window theory inspired policing in major cities, the new edition removed that paragraph and instead replaced it with the following observation:

[…] Psychologists have done studies that show hopelessness can be contagious. […] Ignoring a clearly broken situation reinforces the ideas that perhaps nothing can be fixed, that no one cares, all is doomed; all negative thoughts which can spread among team members, creating a vicious spiral.

The Pragmatic Programmer, 20th Anniversary Edition, pages 6-7.

That strikes me as an enhancing update.

The escalating consequences of degrading quality and perhaps lowered team expectations are likely difficult to visualize. Intuitively though, they are probably varied, deep and costly.


Does it seem like one or two dirty dishes on the counter should not be a big deal at all, but after a day or two, if not managed deliberately, the entire kitchen is in disarray? What about your computer desktop or your email inbox? At some point it was very tidy and well organized, but somehow turned into a cluttered mess, overcrowded, perhaps seeming to spill over. Maybe you feel vaguely bad about it, but it also does not really seem to matter, if you add just a little more to the existing situation.

I bet you can find examples around you.

There are often good intentions, perhaps defined rules. Exceptions lead to informal standards, new “rules.” How do people actually behave with respect to posted speed limits? If you have a doctor appointment at a specific time, when will it actually take place? Do your team meetings begin and end on time? What is the tone of the conversations like in your household? If you are looking at a long-running project, does it seem like it is getting better or worse?

Of course, this does not necessarily fit that.


As so often, it serves to remind ourselves that “all models are wrong, but some are useful” (George Box). It is prudent to explore the nature and limitations of a concept in its original context. Often it is possible to apply it in entirely separate contexts, but of course we need to necessarily ensure we understand in how far the concept applies, i.e. how useful it will be in that context’s reality.

With respect to broken windows then, it is useful to question, whether we are in a situation, where and to what extent it applies. Does compromising on something make it more likely for overall state to be perceived as worse? Would that possibly lead to more such compromises, creating a lower standard of what is acceptable? How likely is it that this would escalate further? Would people care less?

And so forth.


The Pragmatic Programmers advise “do not live with broken windows.” I think that is great. Perhaps one better: Also find ways to encourage better, to make higher standards more likely.


One response to “Broken Windows”

  1. […] 我从这篇文章读到”破碎的窗户理论“,它的出处是一篇发表于1982年的亚特兰大杂志的同名文章。作者认为,可见的忽视迹象会改变人们对环境的看法,并导致更多的忽视,随着时间的推移,情况会变得越来越糟。 […]

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