This study uses data for the 2006/07 maize production season, for the Hlabisa, Dumbe, and Simdlangentsha districts in KwaZulu-Natal, South Africa, to investigate the relative efficiencies of conventional, insect-resistant (Bt), and herbicide-tolerant (RR) maize grown by small-scale farmers. The article fits a stochastic
efficiency frontier using maximum likelihood methods. The resuts show that both GM technologies have very little impact on efficiency and that the tillage system is an important determinant of efficiency levels. This is despite the fact that farmers who used RR seed had substantially higher yields. Higher expenditure on seed cancels out this gain in the efficiency estimates, and there is every reason to believe that these are the better farmers. Employment effects are also investigated, as the RR technology is intended to be labor saving. The
results mostly serve to show how dangerous it is to make any inferences from small sample surveys in one production season.