Table 6 Impact of social capital on the technical efficiency of maize farmers.
Variable | Model ex | Model en |
|---|---|---|
Frontier model | ||
 Constant | 3.68** (2.31) | 3.69*** (7.86) |
 Seed | 0.481*** (4.17) | 0.473*** (10.53) |
 Fertilizer | 0.717*** (3.29) | 0.725*** (12.32) |
 Agrochemical | 0.880*** (2.89) | 0.728*** (9.61) |
 Labour | 0.260*** (7.38) | 0.087*** (4.82) |
 Farm size | 0.339** (6.60) | 0.337*** (7.59) |
Inefficiency model | ||
 Age | − 0.083 (− 0.75) | − 0.225 (− 0.42) |
 Age2 | 0.109 (1.03) | 1.806 (0.04) |
 Household size | − 0.309*** (− 2.61) | − 0.152*** (− 3.21) |
 Years of education | − 0.101*** (− 3.07) | − 0.592*** (− 3.34) |
 Years of experience | − 0.04*** (− 2.66) | − 0.187*** (− 2.78) |
 Gender | 0.523 (0.52) | 0.192 (1.12) |
 Extension visits | − 0.645** (− 2.18) | − 0.450*** (− 2.25) |
 Access to credit | 0.699 (0.19) | 0.330 (0.28) |
 Asset | 0.320 (0.51) | 0.407 (0.22) |
 Dependent variable: ln\(\left( {\sigma^{2} u} \right)\) | ||
  Constant | 2.988*** (3.24) | 3.151*** (4.54) |
  Social capital | − 0.571*** (5.54) | − 0.423*** (10.33) |
 Dependent variable: ln\(\left( {\sigma^{2} v} \right)\) | ||
  Constant | 0.881*** (4.15) |  |
 Dependent variable: ln\(\left( {\sigma^{2} w} \right)\) | ||
  Constant |  | 24.060*** (7.31) |
 \(\eta\) |  | 4.182*** (7.54) |
 \(\eta\) Endogeneity test (X2 = 15.18) |  | P > X2 = 0.000 |
 Mean technical efficiency | 0.681 | 0.646 |
 Log-likelihood | − 937.927 | − 3155.156 |