or unconsciously avoided more dangerous areas when replacing households. However, investigating the possibility, there does not appear to be any evidence that households surveyed before the capture were significantly different in observable characteristics that are unable to adjust to the conflict. Table 1 presents observable characteristics of households surveyed in the third and fourth quarter of 2014. Households surveyed in the third quarter all began their surveys prior to the capture, and households surveyed in the fourth quarter all began their surveys after the city had been captured. Consistent with the capture having little effect on the sampling, column (3) demonstrates that there is little difference between difficult-to-adjust characteristics following the capture of Sana’a. Additionally, column (4) presents estimates of a regression of a fourth quarter indicator on each of the variables analyzed in the table (restricting the sample to households surveyed in the third and fourth quarter), and demonstrates that one cannot reject the hypothesis that the all variables are jointly uncorrelated with the quarter indicator at standard significance levels (p-value of 0.366).<sup>15</sup> While it has been documented that there are no average differences between the households sampled before and after the capture, there still might be differences in specific months. Figures 2a-2c address this concern by reporting confidence intervals for the means of a wide variety of household characteristics are reported by month, as well as the average pre-capture means of each of the variables.

Figures 2a-2c demonstrate that the 95 percent confidence interval of each monthly estimate of difficult-to-adjust control variable contains the pre-capture mean of the variable in the vast majority of instances. Of all the 95 percent confidence intervals reported (180), the pre-capture mean is contained in 96.7 percent of them (174). Importantly, of those confidence intervals that do not contain the pre-capture mean, the distance from the bound of the interval to the pre-capture mean is very small; there is no evidence that any particular variables had a large proportion of monthly confidence intervals that did not contain the pre-capture mean (the maximum for any variable is 2 of the 12 monthly confidence intervals not containing the pre-capture mean); there is no evidence that the post-capture months of October-December were contributing the majority of the instances where the pre-capture means were outside of the confidence intervals (1 of the 7 total instances were from those months); and there is little evidence that the confidence intervals were uniformly larger following the capture of the capital.

However, there is an important data issue to highlight that might affect estimating the impact of capturing Sana‘a. Ramadan occurred primarily in July in 2014, and this might bias expenditure during the pre-period given that consumption patterns are significantly different during Ramadan (e.g., Joliffe and Serajuddin 2012, World Bank 2017). Thus, in specifications that use only the 2014 survey, all households surveyed during Ramadan are excluded from the sample, and the baseline specification uses the three non-Ramadan months prior to the capture of the capital as the pre-period to compare against the three post-capture months

> 15The results are similar when comparing changes between the third and fourth quarter in the rest of Yemen as well (see Appendix 2). The results are also similar when comparing the summary statistics of quarter 1 and 2 to quarter 4 (see Appendix 3).

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