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Table 4 Maximum likelihood estimates of group-specific stochastic production frontier model

From: Improving farm productivity through the reduction of managerial and technology gaps among farmers in Rwanda

Variable Parameter Local varieties OPVs Hybrids Pooled sample
Coefficient std. error Coefficient std. error Coefficient std. error Coefficient std. error
Production frontier
 Constant \({\beta }_{0}\) 5.535** 0.091 5.462* 0.126 5.637** 0.118 5.610** 0.094
 \(\mathrm{ln land}\) \({\beta }_{1}\) 0.106** 0.018 0.105*** 0.006 0.113** 0.011 0.105*** 0.007
 \(\mathrm{ln labor}\) \({\beta }_{2}\) 0.142*** 0.024 0.171** 0.017 0.168** 0.019 0.156** 0.020
 \(\mathrm{ln fertilizer}\) \({\beta }_{3}\) 0.201* 0.106 0.209*** 0.032 0.237*** 0.021 0.206*** 0.014
 \(\mathrm{ln seed}\) \({\beta }_{4}\) 0.128** 0.035 0.138*** 0.021 0.166* 0.047 0.135*** 0.017
Socio-economic variables
 Constant \({\delta }_{0}\) − 2.379 0.152 − 2.794*** 0.054 − 2.984** 0.083 − 2.781*** 0.061
 Age \({\delta }_{1}\) 0.003* 0.010 0.007 0.009 − 0.031 0.015 0.002 0.006
 Gender \({\delta }_{2}\) − 0.795** 0.249 − 0.728*** 0.233 − 0.647*** 0.220 − 0.737*** 0.224
 Education \({\delta }_{3}\) − 0.151*** 0.048 − 0.334** 0.084 − 0.428* 0.131 − 0.237*** 0.060
 Household size \({\delta }_{4}\) − 0.068 0.065 − 0.032 0.052 0.074 0.214 − 0.035 0.057
 Coop. membership \({\delta }_{5}\) − 0.144 0.311 − 0.152 0.339 − 0.313* 0.384 − 0.153 0.376
 Extension services \({\delta }_{6}\) − 0.135* 0.022 − 0.021*** 0.011 − 0.019** 0.009 − 0.027** 0.013
 Credit access \({\delta }_{7}\) 0.192 0.047 − 0.354** 0.097 − 0.213*** 0.030 − 0.272*** 0.029
 Off− farm income \({\delta }_{8}\) − 0.144 0.141 − 0.275 0.406 0.310 0.513 − 0.112 0.112
 Land tenure \({\delta }_{9}\) − 0.326*** 0.317 − 0.352** 0.109 − 0.285*** 0.116 − 0.302** 0.129
 Livestock ownership \({\delta }_{10}\) − 0.801** 0.123 − 0.723*** 0.065 − 0.476** 0.155 − 0.716*** 0.086
Model diagnostics
 Sigma− u \({\sigma }_{u}\) 0.127*** 0.011 0.132*** 0.009 0.122*** 0.020 0.111*** 0.013
 Sigma− v \({\sigma }_{v}\) 0.094*** 0.013 0.079*** 0.008 0.105** 0.009 0.064*** 0.006
 Variance \({\sigma }^{2}\) 0.025*** 0.002 0.024*** 0.003 0.026** 0.001 0.016*** 0.002
 Lambda \(\lambda \) 1.351*** 0.075 1.671*** 0.104 1.162*** 0.022 1.718*** 0.018
 Log likelihood function \(LLF\) − 416.351   − 313.237   − 504.115   − 348.808  
 No. of observations   91 202 67 360
  1. ***, **, and * Statistical significance at the 1%, 5%, and 10% levels, respectively