I find the study poorly done as they only looked at people who took a "Personal Software Process (PSP)" course with an average of 3.7 years of experience. I wo

I find the study poorly done as they only looked at people who took a "Personal Software Process (PSP)" course with an average of 3.7 years of experience. I would assume that people who are extraordinary good at their job will resist taking a course geared towards beginners, so they wouldn't be counted for this study.