[_delirium]

Validity of the observation is a potential confounding factor. There are clearly people who impress their coworkers to the extent that those coworkers believe the person is a 10x-average programmer. That's what this kind of report establishes. But is the judgment of those coworkers correct? Is the person actually 10x more productive in any kind of rigorous, verifiable sense? Generally these reports don't come with enough evidence to establish that.