be for urban areas, which generally may be nearing the upper limit of access (100%) hence, the gap is likely to close with increased _Voice_ .<sup>16</sup> This suggests that improvement in institutions along the lines of which the populace have the ability to participate in selecting government and express freedom through associations and free media can narrow the rural-urban gap.

5.4 ROBUSTNESS, VALIDITY, AND SENSITIVITY In this section we present robustness checks along the lines of sensitivity analysis and validity of our instrumental variable. We also present estimation results from the KLS estimator for both cross-section data and panel data. The latter allows as to control for time fixed effects.

5.4.1 SENSITIVITY ANALYSIS In this section, we conduct sensitivity analysis to ensure that the positive effect of _Voice_ on access to sanitation is not driven by a set of outlier countries or a specific region. To this end, we re-estimate the model with data which exclude countries from one regional grouping at a time from the full sample.

**Table 7:** Sensitivity analysis on the effect of voice on access to sanitation

|||Region E|xcluded in the Es|timation|||
|---|---|---|---|---|---|---|
||South Asia|EAP|MENA|EAP|SSA|LAC|
|_Panel A: Second-stage regression (De_|_pendent variable i_|_s access to sanitatio_|_n)_||||
|Voice and accountability|0.172**|0.214**|0.184**|0.158**|0.184*|0.137|
||(0.075)|(0.094)|(0.080)|(0.065)|(0.104)|(0.097)|
|**AR confdence intervals**|[0.06, 0.43]|[0.08, 0.58]|[0.06, 0.46]|[ 0.05, 0.37]|[0.03, 0.59]|[-0.02, 0.52]|
|Regional dummies|Yes|Yes|Yes|Yes|Yes|Yes|
|<br>Other controls|Yes|Yes|Yes|Yes|Yes|Yes|
|Observations|66|66|63|64|49|52|
|F-stat of excl. instruments|11.42|8.53|10.90|12.34|6.00|7.81|
|Effective F-stat of excl. instruments|8.70|7.91|7.92|10.43|5.39|5.16|
|Kleibergen & Paaptest(pvalue)|0.007|0.012|0.008|0.005|0.026|0.075|

Notes:<sup>_∗∗∗_</sup> ,<sup>_∗∗_</sup> , and<sup>_∗_</sup> indicate significance at the 1%, 5%, and 10% level. Robust standard errors in parentheses. AR confidence intervals correspond to the 95% Anderson-Rubin confidence intervals robust against weak instruments and heteroscedasticity. The _p_ -values of the Kleibergen & Paap (2006) test correspond to a test in which the null hypothesis is that the equation is underidentified, and under the null, the statistic is distributed as chi-squared. ECA is Europe & Central Asia, MENA is Middle East & North Africa, East Asia & Pacific is EAP, sub-Saharan Africa is SSA, and Latin American and Caribbean is LAC.

Table 7 reports the estimates from the sensitivity exercise. All regressions include regional dummies and the standard control variables as in log GDP per capita and the log population density. The results show that there is sufficient evidence of a positive and statistically significant effect of _Voice_ on access to sanitation when a region is excluded from the sample. Specifically, excluding countries in South Asia, Europe and Central Asia (ECA), Middle East and North Africa (MENA), East Asia and Pacific (EAP) or Sub-Sahara Africa (SSA) from the sample does not impact the positive effect or the statistical significance of the effect. However, when Latin America and Caribbean (LAC) countries are excluded from the sample, the coefficient remains positive but statistically insignificant. More importantly, the AR confidence include zero, suggesting that we can not rule out a zero effect for some regions in the sample. However, we note that the fact that five out of the six sensitivity exercise provide strong evidence in support of the conclusion that _Voice_ increases the percentage of people using basic sanitation services is reassuring.

16After all, sanitation use in urban areas is getting close to the upper limit in most regions, hence can only grow slowly while low levels of access in rural areas imply that it can grow faster than in urban areas.

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