You make a good point that hints at another often-undefined assumption in these discussions - 10X performance vs who, exactly? IMO, it should be vs "a typical peer in that profession". For court reporters, if "a typical peer" is a trained court reporter who averages ~200 wpm, and a superstar is at 300wpm, then it's a 1.5X gain. If a "typical peer" is a regular Joe, then 300wpm would be 10X - but this doesn't feel appropriate because we compare productivity of a "10x developer" vs a "typical developer", rather than vs "an average Facebook visitor".