I don't see any flaws that you mention when I read the article. "This doesn’t mean that we can expect 50% of all design projects will have an improvement score

I don't see any flaws that you mention when I read the article. "This doesn’t mean that we can expect 50% of all design projects will have an improvement score within that range. It’s possible your own impact could be a 500% or 5,000% improvement, but our data suggests that an improvement score that high is unusual."