Measuring productivity dispersion: a parametric approach with the Lévy alpha stable distribution
Productivity levels and growth are extremely heterogeneous among firms. A vast literature has developed to explain the origins of productivity shocks, their dispersion, evolution and their relationship to the business cycle. We examine in detail the distribution of labor productivity levels and growth, and observe that they exhibit heavy tails. We propose to model these distributions using the four-parameter Lévy stable distribution, a natural candidate deriving from the generalised Central Limit Theorem. We show that it is a better fit than several standard alternatives, and is remarkably consistent over time, countries and sectors. In all samples considered, the tail parameter is such that the theoretical variance of the distribution is infinite, so that the sample standard deviation increases with sample size. We find a consistent positive skewness, a markedly different behaviour between the left and right tails, and a positive relationship between productivity and size. The distributional approach allows us to test different measures of dispersion and find that productivity dispersion has slightly decreased over the past decade.
Date: 5 December 2019, 15:00 (Thursday, 8th week, Michaelmas 2019)
Venue: Manor Road Building, Manor Road OX1 3UQ
Venue Details: Seminar room A
Speaker: Francois Lafond (INET Oxford)
Organising department: Institute for New Economic Thinking
Organiser: Susan Mousley (INET Oxford Admin Team)
Organiser contact email address: info@inet.ox.ac.uk
Booking required?: Not required
Audience: Members of the University only
Editor: Susan Mousley