# 6 RESULTS<sup>29</sup>

Table 5 reports the results from the DD models of snow pea adoption effects on household consumption and asset status. In terms of household consumption status, we see that over the period of 1985-2005, the surveyed communities witnessed a significant growth across the board, independent of snow pea adoption, as indicated by θ. Focusing on the difference-in-difference estimates of snow pea adoption effects, we see that although the level of consumption increased for all groups between 1985 and 2005, the change seems to have been smaller for stayers in comparison to those that never adopted snow peas, as indicated by Γ1. While Γ2 and Γ3 are negative, they are not statistically significant, indicating that the welfare improvements over the two decades for both leavers and late adopters were not significantly different than the improvements exhibited by non-adopters in the same period.

Moreover, β1 and β2 suggest that by 1985, the level of consumption was significantly higher for adopters (i.e. for both stayers and leavers) in comparison to non-adopters. On the other hand, β3 implies that the 1985 differences in household consumption status between non-adopters and late adopters were not statistically significant. Although this is what we would expect based on the findings of the earlier IFPRI baseline study (von Braun et al., 1989a), we cannot be certain that selection bias in early adoption is not partly responsible for the 1985 differences. Had we had access to survey data dating back to the pre-1979 period, our results would have painted the most comprehensive picture concerning the impact of NTX adoption, as it materialized between 1979, i.e the first year in which the export crops were introduced in the region, and 2005. Since the 1985 differences in welfare levels between stayers and leavers (i.e. the adopters by 1985) and between non-adopters and late adopters (i.e. the non-adopters by 1985) were not statistically significant, the DD estimation could be interpreted as the welfare impact of adoption in the 19852005 period only, given a degree of pre-1985 differences between the early adopters on the one hand and non-adopters and late adopters on the other.

In terms of durable assets, we observe that household asset positions improved significantly for non-adopters and adopters alike throughout the period of 1985-2005. Regardless of the way that the outcome variable is defined, early adopting but leaving snow pea cultivation by 2005 exerts a positive and statistically significant effect on durable asset accumulation. Even though Γ1 for stayers and Γ3 for late adopters are positive, they are not statistically significant.<sup>30</sup> We also see that Γ2 for leavers is statistically different from Γ1 when we use the durable asset index as the dependent variable. Table 6 shows that various measures of favorable dwelling conditions have improved in the survey communities over time, regardless of snow pea adoption status.<sup>31</sup> Γ1, Γ2,

> 29 The findings reported in Tables 5 and 6 stem from estimations that included the complete set of exogenous observable variables, as reported in Section 5. Full regression results are available upon request.

> 30 When we differentiate between leavers and stayers among the late adopters, and estimate durable asset regressions, we see that the increase in durable assets appears to be lower among late adopter stayers in comparison to non-adopters, while the opposite result surfaces from the comparison of late adopter leavers with non-adopters. 31 As demonstrated by Ai and Norton (2003), the coefficient of the interaction term in nonlinear models, such as Probit or Logit for dichotomous dependent variables, is not equivalent to the marginal effect that is calculated by the statistical software. We estimated the marginal effects of the interaction terms reported in Table 6 using the _inteff_ command in Stata and obtained results that were qualitatively similar to those from the linear probability models. These results are available upon request.

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