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Table 4 Regression on covariates, propensity score and Heckman treatment effects (maize farm income per capita as dependent variable)

From: Agricultural extension and its effects on farm productivity and income: insight from Northern Ghana

Variable Regression on covariates Regression on propensity scores Heckman treatment effect
Coefficient SE Coefficient SE Coefficient SE
ACDEP extension 0.135 0.120 0.113c 0.063 1.113a 0.192
ACDEP pscore    3.663a 0.749   
Distance to local market − 0.142a 0.029 − 0.136a 0.036   
Distance to regional market − 0.037b 0.014 − 0.019 0.088   
Gender of household head 0.165 0.138 0.136 0.131 0.209 0.121
Formal education 0.009 0.011 0.024b 0.007 0.014a 0.012
Household size 0.091a 0.011 − 0.117a 0.011 0.097a 0.012
Farming experience 0.002 0.006 0.021a 0.007 − 0.008 0.006
Access to credit 0.052 0.159 0.801a 0.232 0.179b 0.018
Membership of FBO 0.138 0.137 0.030 0.122 0.309a 0.049
Number of maize farm plots 0.106 0.093 0.319b 0.125 − 0.025 0.107
Farm size (maize) 0.345a 0.043 0.217a 0.048 0.312a 0.048
Constant 6.228a 0.206 5.596a 0.235 6.040 0.234
Adjusted R-squared 0.535   0.585    
Lambda      0.632 0.107a
LR Chi2(1) = 13.43      0.000*  
Breusch–Pagan/Cook–Weisberg test
 Chi2(1)   0.380 0.240    
 Prob > Chi2   0.538 0.622    
 VIF (mean)   1.390 2.65    
 Observations 200   200   200  
  1. *denotes significance level of LR Chi2 and it is at 1% level
  2. a,b,cdenote significance levels at 1, 5 and 10%, respectively