Interdisciplinary Urban Sociology of Municipal Rent Arrears Mediation Fee Waivers and Landlord Eviction Filing Withdrawal in Nairobi's Tenement Wards: A Regression Discontinuity of Waiver Eligibility

Municipal rent arrears mediation programmes in Nairobi's tenement wards offer fee waivers to landlords who agree to withdraw eviction filings and enter mediation, yet the sociological question of whether such waivers actually change landlord behaviour has been obscured by a methodological one: the eligibility threshold that determines who receives a waiver is not randomly assigned, and conventional before-after comparisons cannot separate the waiver's effect from the selection of cases into eligibility. Using a before-after-control-impact estimator with between-cluster standard deviation of 6.0, residual standard deviation of 4.5 and intraclass correlation of 0.64, power was estimated across 2000 replications per design cell for cluster counts of 8, 16, 24 and 32 and effect sizes of 3, 5 and 8 percentage points.54 clusters are required to detect a 5 percentage point effect at 80 per cent power, that the minimum detectable effect falls steeply as clusters increase from 8 to 32, and that the intraclass correlation of 0.64 imposes a design effect that makes small cluster counts unreliable for policy inference. The contribution is a design framework that treats the waiver threshold as an identification device rather than a nuisance, and that specifies the cluster counts at which a Nairobi tenement ward evaluation would be credible.