From 2007 through 2011, total Medicaid/CHIP enrollment increased substantially among both ELE and the 41 non-ELE states (data not shown). Total Medicaid/CHIP enrollment among all 8 ELE states increased from 4.18 million to 5.15 million from the first fiscal quarter of 2007 to the last fiscal quarter of 2011, representing an increase of 23 percent. The remaining 41 non-ELE states experienced a fairly comparable percentage increase in Medicaid/CHIP enrollment over the same period, with aggregate enrollment increasing by 24 percent, from 25.0 million to 31.1 million. Medicaid enrollment growth from 2007 to 2011 among ELE states was 2 percentage points higher than the growth rate among non-ELE states. Separate CHIP enrollment among non-ELE states steadily increased over the period as well, but CHIP trends among ELE states varied, as described in the following pages.
Figures IV.1 and IV.2 show the trends in average Medicaid/CHIP and Medicaid enrollment among the eight ELE states, the chosen comparison states, and the excluded non-ELE states. Both figures show that ELE and comparison States had comparable enrollment trends before 2009; the average 2007–2008 quarterly growth rate was approximately 0.4 percent among the ELE and comparison states in the Medicaid model (Figure IV.1) and 0.3 percent in the Medicaid/CHIP model (Figure IV.2). Figures IV.1 and IV.2 also show that, from 2009 to 2011, there were no noticeable differences in average enrollment among the ELE and comparison states. However, the descriptive data highlight quarter-to-quarter changes in enrollment only among ELE and non-ELE states and do not provide an estimate of the causal effect of ELE. By taking into account the scattered implementation of ELE policies and controlling for prevailing trends, fixed differences across states, and time-varying effects such as changes in the economy or state policy, the multivariate analysis provides a more accurate characterization of the overall effects of ELE on Medicaid/CHIP enrollment.57
57 The simple difference-in-difference model, which includes only state and quarter dummy variables
(described in the multivariate results section) indicates that ELE states had higher enrollment growth after they
implemented ELE relative to before they implemented it, compared with the changes in enrollment growth found in
the non-ELE comparison states.