To assess the potential production and income gains under various frontier attainment scenarios, Table 7 presents potential gains in terms of both kilograms and monetary values, for the specific plot as well as household level estimates. Household estimates are derived based on total area cultivated with maize by the household, which itself is imputed via multiple imputation methods to adjust for bias in self-reported area estimates.<sup>18</sup> A key assumption underlying the household level estimates is that the household experiences the same level of productivity on all maize plots. The reported USD values of potential maize production gains are based on the November 2015 Famine Early Warning Systems Network (FEWSNET) Uganda Price Bulletin kilogram unit price, and do not account for any additional expenditures required to attain the increased level of productivity.<sup>19</sup> If suitability-class-specific productivity gaps were closed such that all farmers were operating on their respective MAPS-based productivity frontier, the best-case scenario given soil constraints, households could produce an additional 208 kg, or USD 90, per bi-annual agricultural season, on average.<sup>20</sup> Households classified as S3 under MAPS, assuming the suitability level is the same across all maize plots in the household, only have the potential to earn an additional USD 56 per agricultural season, while those in the highly suitable (S1) category can earn USD 171 more. Reaching this MAPS-based class-specific frontier has asymmetric benefits for female- and maleheaded households, with male-headed households earning USD 99 on average and female-headed households only USD 73.

The benefits of operating at this frontier also differ across the wealth distribution, with those in the poorest tercile having the potential to earn USD 77 per season, USD 28 less than those in the richest tercile. If soil constraints were addressed such that all households were able to operate at the S1 frontier, households on average could increase production by 549 kg, or USD 237, per biannual agricultural season. In this optimistic scenario, asymmetric benefits are still observed, particularly by gender of the household head where female-headed households still, despite reaching the S1 frontier, stand to gain less production than male-headed households.

Finally, the MAPS stochastic frontier analysis and the resulting production frontier are anchored in the current management practices and technology set used by farmers. We make an additional

> 18 While the plots selected for soil sampling were measured with handheld GPS devices, all other plots were only measured via farmer self-reported estimate. Following the evidence and methodology set forth by Kilic et al. (2017b), we use multiple imputation to impute GPS area measurements based on a number of observable characteristics including the farmer reported area. Multiple imputation was conducted by linear regression model including the covariates found in Annex Table A6, with 50 imputations conducted. Note that the farmer reported area did not significantly differ across plots that did and did not have a GPS measurement. The mean GPS-based area of the plots which have an original GPS measure is 0.146 hectares (n=840). The mean of the imputed-GPS measures is 0.148 hectares (n=2437, which includes all cultivated plots regardless of crop).

> 19 The FEWSNET unit price for maize grain is approximately 1450 UGX (https://goo.gl/JFs8d7), or 0.432 USD (using an exchange rate of 1 USD: 3354 UGX, a historical rate from November 30, 2015 from https://goo.gl/HHkfVu).

> 20 AFSIS-based production comparisons are excluded from this particular analysis due to the low incidence and inconsistent suitability classifications found in the S1 and S3 categories.

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