I used to "measure" productivity as part of expert witness testimony in U.S public utility rate cases, so I'm not ignorant of the difficulty of doing so (as you

I used to "measure" productivity as part of expert witness testimony in U.S public utility rate cases, so I'm not ignorant of the difficulty of doing so (as you expand on). It's precisely that difficulty in calculation that I see as one clue among many that the optimization task the Fed attempts is not better than the market for money.