Saturday, August 20, 2011

Measuring Code Quality

A common measure for code quality is to measure Cyclomatic Complexity. Cyclomatic Complexity is used to measure the number of linearly independent paths through a program’s source code. The more conditionals (if statements) or the more loops (for, while …), then the more branches run through the code and thus the code becomes more complex. But what is considered to be a good number for Cyclomatic Complexity? What should developers target?

A study by energy ( reveals the following:

There is a 50% chance of errors with a Cyclomatic Complexity of 38 and almost a 100% chance of error when Cyclomatic Complexity is 74. On the other hand, with a Cyclomatic Complexity of 11, the chances of errors drops to 28%.

So based on this study and the above graph, shoot for a Cyclomatic Complexity of below 20 per class.

Adapted from "Technical Debt Assessment and Reduction" @ Agile2011