Can producer groups improve technical efficiency among artisanal shrimpers in Nigeria? A study accounting for observed and unobserved selectivity

Agricultural and Food Economics

Table 9 Effect of group membership on input costs

	Total variable costs^a	Fuel cost^b	Labor cost^b	Leader cost^b
	Coeff	Coeff	Coeff	Coeff
MEMBERSHIP	− 14.48** (7.03)	− 332.16** (155.97)	− 6739.38* (3660.02)	− 5196.67** (2594.33)
Control variables	Yes	Yes	Yes	Yes
Location dummies	Yes	Yes	Yes	Yes
EXTENSION residual	1.30 (1.46)	7.05 (32.46)	1104.78 (761.68)	1014.66* (539.90)
CREDIT residual	− 0.40 (1.97)	11.11 (43.78)	− 537.43 (1027.29)	− 687.88 (728.17)
Constant	− 5.72* (3.12)	180.49 (69.25)	1495.24 (1625.09)	647.96 (1151.91)
Number of obs	350	350	350	350

***p < 0.01, **p < 0.05, *p < 0.1. Control variables used in the model were similar to those specified in Eq. (13). Standard errors are presented in parentheses. ^aCoefficients are presented in millions while ^bin thousands and estimations are based on the matched sample. MEMBERSHIP was instrumented using the number of fisher groups at the village level. For full model results, please refer to Tables S2, S3, S4 and S5 in the additional file provided with this study
Source: Authors’ calculation based on survey data