> One widely accepted measure is that of branch coverage, the ratio of basic code blocks that were exercised by some test, to the total number of code blocks in the system under test

I know that statement is true, but WHY is it true? I have never seen anyone look at a coverage report and take any useful action. Instead I see management looking at those reports for a number to rate people on, but no useful action is ever taken. When I've looked at the reports I keep finding trivial code that would be hard to test for little gain.

I eliminated the report and nobody misses it. Instead we report to management total number of tests run (test cases, and each assert). Which is easy to game, but since the number naturally increases fast isn't worth the bother.