For households reporting positive medical expenditures, values can be dis-aggregated into three categories of care: inpatient, outpatient and medicine purchases. Panel A.1. of Table 1 also reports descriptive statistics of these outcomes. Medicine purchases were lower after NHIS introduction, and represent 80% of the total medical expenditures among households pre-NHIS and 55% post-NHIS. Outpatient expenditures appear to be larger among households observed after the introduction of the NHIS, possibly as a result of the higher level of care. This difference is small and statistically non-significant. Inpatient expenditures are minimal, as the reported incidence of inpatient care is low in the sample. We opt to omit this variable from our analysis for the same reason.<sup>13</sup> Panel A of Figure 3 displays the OOP medical expenditures (in logarithms) in the months around the introduction of the NHIS. The figure reveals a noticeable drop in OOP payments at the time of NHIS implementation, of similar magnitude when evaluated with a linear fit compared to a kernel-weighted polynomial fit.<sup>14</sup> Our empirical strategy could be underestimating the impact of the introduction of the NHIS if households delay their medical expenditures in expectation to the introduction of the NHIS. If there was anticipation, we might see a dip in the average OOP payments in the months right before the NHIS. Panel A indicates that this does not seem to be the case.

**Health Status.** The GLSS also contains self-reported information on the number of days of illness or injury over the past two weeks. Panel A.2. of Table 1 displays that 53% of the households reported any illness or injury before the NHIS. This share increases to 64% among households observed after the introduction of the NHIS. This may be due to specific reporting behavior because it has been documented that respondents in low- and middle income country settings tend to report their use of medical care instead of their health status (Murray 1996; Bago d’Uva et al. 2008).<sup>15</sup> We use this variable to construct measures of health shock intensity that are not significantly affected by the NHIS and use them to assess effect heterogeneity of the scheme (see next section).

> 13We expect that omitting inpatient expenditures from our analysis induces small consequences for our understanding of the reform, as the NHIS did not offer additional coverage than MHOs on inpatient care.

> 14In our sample, seven households were interviewed during the first two weeks of the month when their month of interview corresponded to the time of NHIS implementation. This implies that they could have had medical expenditures before the NHIS while being classified as under the NHIS. Our results are fully robust to their exclusion.

> 15As we will discuss in further detail below, this difference could represent an issue for our analysis, as it may be the result of a change in the composition of households reporting medical expenditures before and after the NHIS. We implement several methods that circumvent this issue in our analysis, and acknowledge that the observed medical expenditures only render low bound effects of the impact of the NHIS on OOP spending.

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