Description of variables
| Variables | Variable description | unit | |
|---|---|---|---|
| yi | value of crop output | Birr | |
| x1 | area of cultivated land | hectare | |
| x2 | value of owned farm implements | Birr | |
| x3 | number of oxen days used | oxen-days | |
| x4 | labor used in crop production | labour-days | |
| x5 | fertilizer | kg | |
| x6 | seed used | kg | |
| Vi | a disturbance term with normal properties | ||
| Ui | farm specific error term | ||
| Z1 | age of the respondent in years | number | |
| Z2 | education, i.e. literacy status of the farmer | dummy | 1 = literate, 0 = otherwise |
| Z3 | sex of the house hold head | dummy | 1 = male, 0 = female |
| Z4 | membership to association | dummy | 1 = member 0 otherwise |
| Z5 | off farm income | dummy | 1 = have non-farm income 0 = otherwise |
| Z6 | access to irrigation | dummy | 1 = irrigated, 0 = otherwise |
| Z7 | credit | dummy | 1 = loan taken, 0 = otherwise |
| Z8 | number of crop type2 | number | |
| Z9 | distance to woreda market | km |
Estimates of the inefficiency parameters
| Parameter | Coefficient | Standard-error | t-ratio |
|---|---|---|---|
| Constant | 1.99** | 0.98 | 2.02 |
| Head's sex | 0.63 | 0.69 | 0.90 |
| Head's age | −0.10** | 0.053 | −1.96 |
| Off farm income dummy | 0.75 | 0.44 | 1.52 |
| Extension participation | −0.10 | 0.77 | −0.13 |
| Irrigation | −5.54** | 3.44 | −1.69 |
| credit | 0.14 | 0.38 | 0.38 |
| Distance to market | 0.48 | 1.33 | 1.83 |
| Number of crop type | −0.89** | 0.50 | −1.75 |
| Sigma-squared | 2.72 | 1.02 | 2.64 |
| Gamma | 0.82 | 0.083 | 9.83 |
| log likelihood function | −329.5 | ||
| LR test of the one-sided error | 33.5 |
Estimates of the conventional inputs
| Inputs | Coefficient | Standard-error | t-ratio |
|---|---|---|---|
| Constant | 6.83*** | 0.3 | 22.23 |
| Total seed | 0.027 | 0.016 | 1.6 |
| Oxen-days | −0.02 | 0.02 | −1.32 |
| Fertilizer | 0.01** | 0.008 | 1.33 |
| Farm size | 0.26*** | 0.075 | 3.46 |
| Farm equipment | 0.09** | 0.036 | 2.59 |
| Labour-day | 0.19** | 0.097 | 2.002 |
| Sigma-squared | 0.82 | ||
| Log likelihood function | −346.33 |
Generalized Likelihood ratio test of hypotheses for parameters of stochastic production frontier and technical inefficiency factors
| Null hypotheses | LR | Critical value | Decision |
|---|---|---|---|
| Absence of inefficiency H0: δi = 0 = γ | 33.5 | 29.1a | reject |
| Production function is Cobb-Douglas H0: βji = 0 | 29.4 | 32.7b | do not reject |