That is the recently published (QJE) paper by Douglas Gollin, David Lagakos, and Michael E. Waugh, the abstract is here:
According to national accounts data, value added per worker is much higher in the nonagricultural sector than in agriculture in the typical country, particularly in developing countries. Taken at face value, this “agricultural productivity gap” suggests that labor is greatly misallocated across sectors. In this article, we draw on new micro evidence to ask to what extent the gap is still present when better measures of sector labor inputs and value added are taken into consideration. We find that even after considering sector differences in hours worked and human capital per worker, as well as alternative measures of sector output constructed from household survey data, a puzzlingly large gap remains.
There are ungated copies here.
I believe there is something “funny” about agriculture. Productivity convergence is also slowest in that sector, especially compared to manufactures. I see a few possible factors at work:
1. Status quo bias keeps a lot of workers living in rural areas and employed in agriculture, lowering productivity in that sector and also hindering the transfer of new ideas and technologies. Wages stay low and approaches remain hidebound and old-fashioned.
2. The influence of “non-rational” culture — in the Weberian sense — is usually stronger in rural and agricultural areas.
4. Liquidity constraints limit movement into urban areas.
5. Fear of loss of status and local friendships also limit the movement into urban areas and prevent an equalization of returns as defined in terms of pecuniary variables only.
Or put agriculture aside, and let’s pose the same question about wage equalization in Puerto Rico and the mainland United States, given that free migration is allowed and wages in the U.S. are considerably higher. In a lot of different settings, factor price equalization isn’t as strong as you might think. Maybe this is just showing that agriculture is in fact a remarkably human activity.