Table 4 reports the triple-difference coefficient vector θ estimated from a number of
alternative specifications of the model. The specification reported in the first column of
the table includes only the variables in the vector X, while the specification reported in the second column adds a vector of state fixed effects, and these fixed effects are interacted
with both the time dummy variable (ti), as well as with the immigrant status vector
(I). The state-time interactions capture not only state-specific differences in the level of
health insurance, but also state-specific changes in health insurance coverage rates (induced
perhaps by varying economic and political conditions). Similarly, the state-immigration
status interactions net out the possibility that there may be state differences in health
insurance coverage (and in the trends) across the various immigration status groups. Finally,
the last two columns of Table 4 replicate the regression analysis in the sample of
children