The focus on productivity as the key to economic growth ignores the fact that we can’t directly observe productivity. We need better ways to measure improvements in overall living standards. The great new god of economics, productivity, may have feet of clay. The modern world is a noisy place, but you’ve probably noticed the way economists now give speeches extolling the virtues of “increasing productivity”. Such speeches were much rarer when I became an economic journalist in the 1970s. Why?