Often times when Development Team are looking to do Code Review, reading the numbers out of Cyclomatic Complexity is one of the Top Priorities.

Cyclomatic Complexity is a formula for determining the varying logical paths that can be taken though a piece of code, thus determining a quantitative value for the code’s complexity. A higher Cyclomatic Complexity score means that there are a lot of code paths and/or factors that affect the logic with the code. One way to think about it is this: to fully unit test a method, you should have one unit test for each logic path – thus a score of 10 would result in as many unit tests. Wikipedia entry: http://en.wikipedia.org/wiki/Cyclomatic_complexity

Martin Fowler in his BLOG mentions how to approach reading the metrics and act most effectively - http://martinfowler.com/articles/useOfMetrics.html

Also, I find this as a great read too - http://www.wrightfully.com/thoughts-on-cyclomatic-complexity/

There are also some great publications on MSDN - http://msdn.microsoft.com/en-us/library/bb385914.aspx

A few MSDN BLOGS worth reading  -

  1. http://blogs.msdn.com/b/codeanalysis/archive/2007/11/28/positioning-code-metrics-to-management.aspx
  2. http://blogs.msdn.com/b/zainnab/archive/2011/05/17/code-metrics-cyclomatic-complexity.aspx
  3. http://blogs.msdn.com/b/codeanalysis/archive/2007/10/03/new-for-visual-studio-2008-code-metrics.aspx