Lately I've been interested in applying static analysis to PHP projects. Static analysis is the process of analysing software code - in our case PHP source code -, without actually executing the (compiled) result of the source code you're analysing.

He mentions some types of analysis and some of the tools that can be used to measure it. He also talks about issues it can help with (like the potential for harm if a part of code is changed) and a pointer to the Pixy software he used to generate the statistics (and images like this).

I tried out the Pixy XSS and SQLI Scanner (http://pixybox.seclab.tuwien.ac.at/pixy/index.php) on a few simple PEAR files. On the first, I got a java exception, on the second it was unable to resolve the simplest of includes (no ability to resolve include_path). In short, the thing is useless for anything written using PEAR. Fun!

The Pixy XSS and SQLI Scanner is made to find SQL and XSS injection issues in scripts. It runs as a Java application and scans PHP4 source code to try to find problems. For more information on the scanner or to try it out for yourself, check out the project's homepage for documentation and downloads.