Predicting medium-term TFP growth in the United States: econometrics vs ‘techno-optimism’

We analyse TFP growth in the US business sector using a basic unobserved component model where trend growth follows a random walk and the noise is a first order autoregression. This is fitted using a Kalman-filter methodology. We  find that trend TFP growth has declined steadily from 1.5 to 1.0 per cent per year over the past 50 years. Nevertheless recent trends are not a good guide to actual medium-term TFP growth. This exhibits substantial variations and is quite unpredictable. Techno-optimists should not give best to productivity pessimists simply because recent TFP growth has been weak.