Does contract farming affect technical efficiency? Evidence from soybean farmers in Northern Ghana

Selorm, Ayeduvor; Sarpong, D. B. S.; Egyir, Irene S.; Mensah Bonsu, Akwasi; An, Henry

doi:10.1186/s40100-022-00240-9

Agricultural and Food Economics

Table 7 SPF estimates using unmatched sample

From: Does contract farming affect technical efficiency? Evidence from soybean farmers in Northern Ghana

Variables	Conventional SPF						Sample selection correction SPF
	Pooled		Contract farmers		Non-participants		Contract farmers		Non-participants
	Coeff.	Z-stat	Coeff.	Z-stat	Coeff.	Z-stat	Coeff.	Z-stat	Coeff.	Z-stat
Constant	0.036	0.46	− 0.116	− 0.96	0.127	1.24	− 0.299**	− 2.11	− 0.014	− 0.12
Labor	0.290***	4.77	0.266***	2.73	0.318***	4.02	0.239**	2.42	0.291**	2.26
Fertilizer	0.041***	3.27	0.053***	2.65	0.030*	1.94	0.057**	2.31	0.027	1.37
Seed	0.567***	3.71	0.509**	2.04	0.630***	3.20	0.567***	2.75	0.644**	2.16
Herbicide	− 0.143***	− 3.47	-0.206***	− 2.93	− 0.136***	− 2.67	− 0.211***	− 3.10	− 0.128**	− 1.96
Labor²	0.218***	4.02	0.289***	3.00	0.194***	2.86	0.258***	2.60	0.196**	2.45
Fertilizer²	0.001*	1.85	0.001	1.38	0.001	1.26	0.002*	1.77	0.001	0.96
Herbicide²	− 0.024***	− 2.64	− 0.021	− 1.13	− 0.025**	− 2.35	− 0.020	− 1.25	− 0.028***	− 2.66
Seed²	0.025	0.48	0.150	1.49	− 0.007	− 0.11	0.148	1.45	− 0.029	− 0.36
Labor × Fertilizer	− 0.012	− 1.57	− 0.015	− 1.24	− 0.008	− 0.89	− 0.016	− 1.41	− 0.010	− 0.94
Labor × Herbicide	− 0.020	− 1.05	− 0.049	− 1.49	− 0.002	− 0.09	− 0.042	− 1.39	− 0.010	− 0.35
Labor × Seed	− 0.216***	− 3.26	− 0.164*	− 1.70	− 0.239**	− 2.48	− 0.173	− 1.48	− 0.254*	− 1.80
Fertilizer × Herbicide	− 0.001	− 0.55	− 0.002	− 0.52	− 0.002	− 0.47	− 0.002	− 0.56	− 0.001	− 0.39
Fertilizer × Seed	− 0.005	− 0.92	− 0.011	− 1.25	− 0.002	− 0.27	− 0.011	− 0.89	− 0.001	− 0.13
Herbicide × Seed	0.033	0.64	− 0.053	− 0.50	0.048	0.80	− 0.064	-0.69	0.073	1.06
Power Tillage	0.089**	2.20	0.169***	2.93	0.028	0.48	0.163***	2.94	0.018	0.29
Bawku West District	0.151**	2.47	0.179*	1.88	0.150*	1.88	0.194**	2.11	0.149	1.51
Nanumba South District	0.211***	3.26	0.234**	2.35	0.180**	2.10	0.242***	2.63	0.167	1.53
Karaga District	0.118*	1.75	0.048	0.47	0.168*	1.89	0.058	0.62	0.144	1.38
Variance	0.504***	7.38	0.487***	4.86	0.517***	6.45
Lambda	1.031***	8.9	0.863***	5.09	1.308***	7.47
Sigma (u)							0.414***	4.51	0.537***	7.62
Sigma (v)							0.377***	7.56	0.384***	10.66
Rho							0.775***	2.63	0.925***	8.19
Log-likelihood ratio	-283.275		-126.887		-147.556		-317.068		-315.771
Returns to scale (RTS)	0.970		0.748		0.800		0.732		0.770
No. of observations	531		235				235		296

Legends: ***, **, * represent significance levels at 1%, 5% and 10%

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