We found that on average the growth rate of industry-level real value added was substantially lower under double deflation than under single deflation, and the year-to-year volatility of growth rates was much higher under double deflation. We also found that with these estimates, GDP would have grown substantially more slowly than the official estimate for 1997- 2015. Our theoretical work on double deflation suggests that it is possible to implement double deflation in such a way that there is no effect on the headline growth rate of GDP. This requires using a comprehensive set of deflators which are currently not publicly available. It is possible, however, that even on this approach the industry-level estimates of real value added may be quite different from the current official ones.
Our analysis of the productivity slowdown using detailed industry data pointed to the importance of economy-wide and indeed global explanations for the slowdown. Also, the UK productivity growth puzzle is concentrated in sectors where productivity is difficult to measure, such as information and communication and finance, suggesting that measurement issues should not be dismissed as part of an explanation of the puzzle.