Productivity
Also called: labour productivity, total factor productivity, TFP
Productivity is output per unit of input, usually per hour worked, and it is the only sustainable source of rising living standards. Real wages track it closely over long periods, which is why a productivity slowdown shows up as stagnant pay a decade later. Total factor productivity captures the part not explained by more capital or more labour — effectively the measure of how much better we've got at combining them.
Where this is taught
Definitions are the trailer. These free levels turn Productivity into something you play — one bite-size lesson, with worked examples, a quiz and XP.