Scientific Process

First you understand the problem that you are trying to fight (code complexity/unmaintainable software,)

you research ways to quantify it (the metrics,)

you create some tool or device to extract that information from your subject,

you extract the metrics from a familiar subject,

you apply your knowledge of how #2 relates to #1 and improve the subject under analysis,

you use the tool to verify the metrics have improved,

time shows you that the changes you made indeed reduced the problem at #1