Table 5. Weight-for-age z-score (children aged <5 y), ascertained at last round of data collection.
| Intermittent Supply | Continuous Supply | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| N | Mean z-score (SD) | N | Mean z-score (SD) | Δz | 95% CI a | Adjusted Δz b | 95% CI a | Regression p-value | Permutation test p-value c | |
| All observations d | 1,765 | −1.59 (1.14) | 1,811 | −1.58 (1.12) | 0.01 | (−0.07–0.09) | 0.01 | (−0.07–0.09) | 0.79 | 0.67 |
| Subgroup analysis by wealth | Interaction p-value e | |||||||||
| Above median wealth | 934 | −1.48 (1.20) | 935 | −1.48 (1.15) | −0.01 | (−0.12–0.11) | 0.01 | (−0.11–0.12) | 0.95 | -- |
| Below median wealth | 829 | −1.71 (1.07) | 870 | −1.68 (1.09) | 0.03 | (−0.07–0.14) | 0.01 | (−0.10–0.13) | -- | -- |
| Subgroup analysis by rainfall | Interaction p-value e | |||||||||
| Dry period (>10 d after rain) | 1,610 | −1.59 (1.14) | 1,596 | −1.60 (1.13) | −0.01 | (−0.09–0.08) | −0.01 | (−0.10–0.07) | 0.10 | -- |
| Wet period (<10 d after rain) | 155 | −1.57 (1.19) | 215 | −1.39 (1.03) | 0.17 | (−0.08–0.41) | 0.21 | (−0.03–0.45) | -- | -- |
Abbreviations: CI, confidence interval; SD, standard deviation.
a CIs obtained by bootstrapping within strata of wards with clustering at household level.
b Adjusted for household socioeconomic status, religion, handwashing infrastructure, latrine ownership, sewerage, and garbage disposal; we only included covariates in the adjusted models that could not plausibly be impacted by the continuous supply intervention.
c p-value from Wilcoxon rank-sum permutation test; the permutation test is conservative relative to the CIs around the PR because it tests the null hypothesis that the two groups have the same distribution as opposed to the null hypothesis of no effect on average.
d We excluded children with z-scores >5 or <−5 from the analysis.
e p-value for interaction from generalized linear model with interaction terms.