One day a major Utah corporation retained mystery shoppers to evaluate one of its most visibly promoted services, which they provided at the time in 10 different facilities. Unfavorable reports came back. Accordingly, the organization took the negative feedback to heart and made much-needed improvements.
Ha ha, just kidding. The 10 managers flew into a rage, so their boss canned the report. I know. I was in the rage-filled meeting, too concerned for my safety to raise a futile voice of dissent.
The moral? Only convenient research results are valid.