Peer Reviews

"Peer reviews are a waste of time", "Peer reviews don't help", "We don't have time to peer review the", peer reviews are evil, blah, blah blah! I've heard this for years and all I can say to this is "Bologna!" A second or third pair of eyes on something is useful. Haven't you ever had a problem while debugging code and said "Hey Bob, can you take a look at this" and then either through your explanation or something Bob says you have an "a-ha" moment can get past the problem? A peer review is like trying to get to the "a-ha" moment before you realize you need to.

Statistics have shown that Peer Reviews do help if they're done right. (see the book “Best Kept Secrets of Peer Code Reviews” by Jason Cohen.

First, some good reasons to do peer reviews. The best reason is defects found early cost less to fix, simple economics. A second pair of eyes can help. Another reason is that less experienced programmers can learn from more experienced programmers at peer reviews. One note is that typically everybody can learn something from other peoples code.

Second, to shoot down some myths. People have a lot of reasons to not do Peer Reviews. Things like "my code is already good enough". To this I have to ask, have you ever had any problems with your code? If you answered No then you are better than any of the Rock Star programmers that I've heard about. Peer reviews are to get rid of problems before they get out.

How about “We don't have time for peer reviews.” Then how much time do you have to fix problems later? And how much will it cost?
Another myth is that peer reviews don't help. They don't help if you don't do them. They don't help if you don't really review the code. If you find just a few defects it can be worth doing it. My Mom and Dad used to say “Anything worth doing is worth doing right”.

There are alway excuses for not doing peer reviews, but no good reasons.
People have ego problems with peer reviews, too. There's the “Big Brother” effect where programmers feel like the peer review is to monitor their every move. This is not how it should be, it should be about removing defects and not about monitoring.

Earlier I said peer reviews help if they're done right. That means the code is really reviewed, the reviewers read over the code and look for potential problems, makes sure it meets the requirements, and is understandable. If this is done then defects are found and fixed. If the code is just glanced over, fewer defects are found, problems are found later and costs more to fix.

To close there are some truisms about Peer Reviews:


1) Hard code has more defects – the more complex the code, the more potential defects.
2) More time yields more defects – The more time spent reviewing the more defects found
3) It's all about the code – Review the code not the programmer
4) The more defects the better – Defects found early are cheaper to fix

The bottom line is a better product and that's what peer reviews should be all about. Happy reviewing!