Could the Debate Be Over? : Errors in Farmer-Reported Production and Their Implications for the Inverse Scale-Productivity Relationship in Uganda
Based on a two-round household panel survey conducted in Eastern Uganda, this study shows that the analysis of the inverse scale-productivity relationship is highly sensitive to how plot-level maize production, hence yield (production divided by GP...
| Main Authors: | , , |
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| Language: | English en_US |
| Published: |
World Bank, Washington, DC
2017
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| Subjects: | |
| Online Access: | http://documents.worldbank.org/curated/en/242721505231101959/Could-the-debate-be-over-errors-in-farmer-reported-production-and-their-implications-for-the-inverse-scale-productivity-relationship-in-Uganda http://hdl.handle.net/10986/28369 |
| Summary: | Based on a two-round household panel
survey conducted in Eastern Uganda, this study shows that
the analysis of the inverse scale-productivity relationship
is highly sensitive to how plot-level maize production,
hence yield (production divided by GPS-based plot area), is
measured. Although farmer-reported production-based
plot-level maize yield regressions consistently lend support
to the inverse scale-productivity relationship, the
comparable regressions estimated with maize yields based on
sub-plot crop cutting, full-plot crop cutting, and remote
sensing point toward constant returns to scale, at the mean
as well as throughout the distributions of objective
measures of maize yield. In deriving the much-debated
coefficient for GPS-based plot area, the maize yield
regressions control for objective measures of soil
fertility, maize genetic heterogeneity, and edge effects at
the plot level; a rich set of plot, household, and plot
manager attributes; as well as time-invariant household- and
parcel-level unobserved heterogeneity in select
specifications that exploit the panel nature of the data.
The core finding is driven by persistent overestimation of
farmer-reported maize production and yield vis-à-vis their
crop cutting–based counterparts, particularly in the lower
half of the plot area distribution. Although the results
contribute to a larger, and renewed, body of literature
questioning the inverse scale-productivity relationship
based on omitted explanatory variables or alternative
formulations of the agricultural productivity measure, the
paper is among the first documenting how the inverse
relationship could be a statistical artifact, driven by
errors in farmer-reported survey data on crop production. |
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