Determine the economic productivity level
Up until 1500 as best we can tell there had been next to no growth in output per worker for the average human for millennia. Even in 1800 average human alive had a material standard of living (and an economic productivity level) at best twice that of average human alive in the year 1. The problem wasn't that there wasn't any technological progress. There was. Humans have long been ingenious. Priestly, Warrior and bureaucratic elites in 1800 lived much better than their predecessors in previous millennia had lived. However just because elite that ruled you lived better doesn't mean that you--if you were average--lived any better.