Productivity measures are a myth held over from the 1980S
単位時間あたりの生産量をもって生産性を測ろうとするのは、機械が 1 時間に何個の部品を製造できるかといった、有形のものを対象にしている（物的生産性） タイピング速度や文章の量で作家を評価するようなもの
But measuring intangibles is hard and measuring tangibles is easy, so naturally people gravitate to what is easiest, even when it’s wrong. Better to have some measure rather than nothing—right? No! Give me a fuzzy metric of something valuable (an outcome) rather than a precise metric for something unimportant (an output) any time.