data (Funk et al., 2015).<sup>13</sup> The distance measure (from highly suitable soil), , is included in _X_ for analysis conducted on the full sample, while the membership grades, , are used to EE dd disaggregate the full sample into suitability-class sub-samples upon which the estimations are cc ff conducted separately (discussed in more detail below). Because both pure stand and intercropped plots are included in the sample, a dummy for the cropping pattern and a continuous variable for the seeding rate are also included in the _X_ vector.<sup>14</sup> Inclusion of indicator variables for administrative districts were attempted but were found to be problematic due to correlation with rainfall and other covariates. The error term, , is disaggregated into a symmetric disturbance term, , and a non-negative disturbance, . The symmetric disturbance is assumed to be independently and identically ii ii εε 2 νν distributed with ). It is assumed to be independent of and results from measurement ii μμ error, climate-related shocks that affect production, and other exogenous shocks. The non-negative vv ii NN(0, σσ μμ term, , represents the technical efficiency of the household cultivating the plot, or the distance from the potential production frontier. It is assumed to be from truncated normal distribution, ii μμ2), with a zero-lower bound (Aigner, Lovell, and Schmidt, 1977). Furthermore, is modeled as a linear function of variables that are believed to explain a household’s technical uu ii NN(0, σσ μμ efficiency or ability (Deininger et al., 2007; Kilic et al., 2009): JJ ii jj iijj ii (5) μμ = γγ+ � δδ ZZ + θθ jj=1 _Zi_ is a _J_ -vector of covariates used to explain technical efficiency, which includes plot manager age, an indicator for the manager’s attainment of primary education, an indicator for whether the plot manager received agricultural extension services, the dependency ratio of the household, and the number of agricultural assets owned by the household. Uncertainty around climatic factors, which may influence farmer behavior with respect to farming practices, is proxied by the coefficient of variation of flowering season rainfall (over the period 1999 – 2014), which is also included in _Zi_ . Additional controls were initially included, such as gender of the plot manager and seasonal rainfall shocks, but due to correlation with other covariates and lack of explanatory power in linear regressions, these were ultimately excluded. Indicators of access to credit and public infrastructure could theoretically be included in _Z_ , although data on these covariates are not available for this

> 13 The onset of the season is defined following the Water Requirement Satisfaction Index (WRSI), such that the season begins when at least 25mm of rain falls in one dekad, and a total of at least 20mm of rain falls in the subsequent two dekads (documentation available here: https://goo.gl/sgmTK8).

> 14 Pure stand plots are those on which only maize is grown. Intercropped plots are those on which maize and at least one other crop is grown. The “seeding rate” included here is a ratio of the quantity of maize seed used on the plot to the quantity of seed that would have been used had the farmer planted only maize. The seeding rate is, therefore, bounded (0,1] and equals 1 for all pure stand plots. The seeding rate is included in addition to the dummy variable for cultivation pattern because it is believed that some combinations of crops could improve potential maize yields.

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