To test the predictions of the model of this paper, the growth analysis is further extended to include the share of the rural population concentrated on less favored agricultural land and the share of the workforce employed in industry as additional explanatory variables.5 The latter variable is from World Bank (2013), averaged over the 5 years preceding 1990 to avoid endogeneity problems.
I have experimented with all of these in the regressions as additional explanatory variables, but none were consistently significant in estimates of models 8 and 9, and they did not affect the main coefficients of interest.
Third, although our study provides a framework for producing highly spatially resolved models for childhood lead exposure risk, in some geographic areas additional explanatory variables may be needed, as was the case, for example, in Detroit.
This indicates that not only classroom attendance contributes to this relationship, but also that advance quizzing in the classroom provides additional explanatory power.
Social influence, though correlated with intention to use (Pearson r = .25, p < .001) in the bivariate analysis, did not have any additional explanatory power in the regression.
In order to assess whether this was indeed the case, Table 13 presents results using the two-equation specification of Table 11, but in which schooling is now included as an additional explanatory variable in the growth regression.
We furthermore tested whether consumption explained away the relationship between model-based-index and devaluation sensitivity, by including it as an additional explanatory variable in our linear regression in which per-subject devaluation sensitivity was the dependent measure and the per-subject model-based index, consumption, and their interaction were predictors.
The analysis estimates the increase in model fit associated with each predictor variable by averaging its additional explanatory power in all models (i.e. all possible combinations of the predictor variables) in which that variable appears [44].
It can be debated whether to include additional explanatory factors in the statistical models of this study in order to account for potential confounders.
Temperature estimates are improved substantially over these lapse rate estimates by including measures of relative radiation and relative slope position as additional explanatory variables in the model.
