Broken Windows

Broken Window Theory is an extremely powerful concept.  Here's a short article about it:

http://en.wikipedia.org/wiki/Broken_windows_theory

And here is the original article that started it all:

http://www.theatlantic.com/magazine/archive/1982/03/broken-windows/4465/

It was first developed with respect to criminology, but it has very far-reaching implications.  Malcom Gladwell expounds on the sociology of it in The Tipping Point.  And Steve McConnell applies it to Software Engineering in Code Complete, mentioned last time.   

Why is it so powerful?  If you read the above Wikipedia article I'm sure you can see why: small changes to an environment invoke large changes in the minds of the people therein. 

I don't want to repeat what the article says (please do read it) but in short, here's the point:

An investigation of urban areas was performed to determine what transforms a good neighborhood into a bad neighborhood.  The answer: broken windows. 

When people see broken windows in buildings, it sends them a signal that nobody cares about that area.  So vandals come and break more windows, in addition to other types of destruction.  This is now a stronger signal that nobody cares and that disorder rules.  So crime escalates.  It is a self-perpetuating downward spiral.  And it all starts from broken windows.

The solution is clear: fix broken windows.  New York City tried exactly that starting in 1985.  It first applied the principle to the subway system and then the city in general.  The results were striking.  Changing this small signal drastically improved crime rates.

Again, you can see the import of this.  The broken window is simply a metaphor.  What matters is the signal.  If we want people to follow some norm, we need to ensure signals are in place to encourage such behavior.  Perhaps even more importantly, we need to remove signals that encourage the opposite behavior.

Here's a really simple example.  Let's say you have some roommates and you want them to keep the place clean.  If they see "broken windows" (again, a metaphor here: perhaps a few unwashed dishes, or a dirty floor) what signal are you sending?  That you don't care about cleanliness!  Which is the opposite signal that you want to send.

So anytime we want to encourage a certain social norm, we need to fix broken windows.  They may seem like little things, but that is exactly the point!  The little things are always noticed, at least on some level. 

After learning about this, I started to see broken windows everywhere (especially in code we were writing).  It is worth the time investment to fix them.