Rural Interdisciplinary Sociology of Borehole Water-Tariff Committee Chair Election Margins and Non-Revenue Water Losses in Tanzanian Village Water Trusts: A Regression Discontinuity Analysis of Election Thresholds

Village water trusts in rural Tanzania elect borehole water-tariff committee chairs by majority vote, and the margin of victory is widely treated as an administrative detail rather than a determinant of revenue performance. Because no observational data are available, the paper characterises the operating characteristics of the proposed design under a declared variance structure: between-cluster standard deviation of 6.0, residual standard deviation of 4.5, and intraclass correlation of 0.640. Power was estimated across 2000 design cells defined by cluster counts of 8, 16, 24 and 32 and effect sizes of 3, 5 and 8 percentage points. The analysis indicates that 52 clusters are required to detect a 5-percentage-point effect at 80 per cent power. The electoral-margin discontinuity is a credible identification strategy for the sociological study of water-trust governance, but that its data demands exceed what most village-level evaluations can supply. The contribution is a design template and a power benchmark for future fieldwork, not an empirical estimate.