Financial markets and economic data are seemingly at odds in their verdicts on the health of our economy. According to the stock market, we are in a nirvana of accelerating technological change. But according to the economic data, the past decade has had some of the slowest productivity growth since the start of the Industrial Revolution.

The market implies that innovation is thriving, as giant US technology companies reach ever-higher valuations. The data says it has stopped. The contrast between these two measures has led many to dismiss the economic data as a problem of mismeasurement. However, there is no evidence of additional unobserved economic growth in either wages or profits.