The definition says “output per hour worked” When you measure this at the level of the whole economy, you can think of the numerator as being the country's GDP

The definition says “output per hour worked” When you measure this at the level of the whole economy, you can think of the numerator as being the country's GDP, and the numerator as the number of hours worked by all employees. But how do you measure worker output? Great question, and that is exactly my point: in many modern businesses (and hence in the economy as a whole) 'labor productivity' is not a measure of worker output. Imagine an economy in which everything has been automated, and everyone is unemployed and living on welfare, except the one guy to turn the machines on and off. He is paid $100k for a not-very-demanding job. Now you calculate labor productivity, and it's a gazillion dollars per labor hour, the highest it's ever been. At the same time the (ex-)workers are as unproductive as they have ever been, because their skills are no longer applicable to any useful activity. Consider the times in your career when you were most productive (in the everyday sense of the word). Do those coincide with the times when you worked at a company that high the highest profit per employee-hour? Maybe, maybe not.