UK productivity growth has been puzzlingly slow since the crisis. After averaging 2% every year in the pre-crisis decade, growth in labour productivity (output per hour worked) has slowed to an average of only 0.5%. Extensive research and commentary on the productivity puzzles has suggested myriad causes for the malaise – including ‘zombie’ firms hoarding resources, sluggish investment in the face of uncertainty, mismeasurement and more – and have dismissed others that no longer seem plausible – including temporary labour hoarding. Using firm-level data, I show that slower aggregate growth is entirely driven by the more productive firms in the economy.
Last year I published a post arguing that there are two productivity puzzles – one in the level and the other in the growth rate of labour productivity – that contained an error. In the original blog, I showed that we could decompose the puzzle(s!) into contributions from either slower than trend growth in capital services per hour worked (capital deepening) or technology growth (TFP).
Much has been written about the productivity puzzle. But there are actually two puzzles apparent in the data – one in the level that hit at the crisis and the other in the growth rate, which is a more recent phenomenon – and they could be driven by completely different sources. Distinguishing between the two puzzles is important precisely because of these potential differences – if anyone analyses the puzzle as a whole looking for the force driving it, the actual underlying variety will confound our estimates of the relative importance of these drivers.
In this post I discuss:
- what people mean by the productivity puzzle, usually a percent deviation from the pre-crisis trend;
- how I think of it as actually two puzzles: one in the level and the other in the growth rate; and
- why this distinction can be important, using the example of a simple growth accounting decomposition of productivity growth into capital deepening and technological advancement.