Don’t test more, develop better...

The following quote by Steve McConnell emphasizes on importance of processes in software projects. Poor quality results from weak process structure. Processes that enable teams to do "right" things first time not only improve the overall effectiveness but also improve the quality. Test results are just a measure of the overall product quality.

Testing by itself does not improve software quality. Test results are an indicator of quality, but in and of themselves, they don't improve it. Trying to improve software quality by increasing the amount of testing is like trying to lose weight by weighing yourself more often. What you eat before you step onto the scale determines how much you will weigh, and the software development techniques you use determine how many errors testing will find. If you want to lose weight, don't buy a new scale; change your diet. If you want to improve your software, don't test more; develop better.-

Steve C McConnell, "Code Complete: A Practical Handbook of Software Construction" by Steve C McConnell, ISBN: 1556154844