The league wide batting average in the MLB was .253 in 2013 (first Google result, I&#x27;m assuming it doesn&#x27;t vary all that much between seasons). While you are correct that hitting 0.6% compared to 0.5% doesn&#x27;t mean much the numbers I responded to were meaningful in an MLB context (.250 vs. .300) so I think it&#x27;s justified to use relative differences. In fact I think it&#x27;s more insightful than using absolute numbers. Speaking of a 5% increase in that context is confusing (at least to me :D) when in reality the skill is roughly 20% above league average.
A programmer who is 20% above average will certainly command a premium as will a salesperson.