Urban Sociology of Metropolitan Land Value Capture Betterment Levy Assessment Appeals and Developer Permit Withdrawal in Nairobi's Redevelopment Corridors: A Bunching Estimation of Valuation Thresholds

The central problem is that appeals data are observed only for developers who choose to contest an assessment, and the decision to contest is itself a function of the valuation threshold that the levy schedule imposes. A bunching estimation strategy is proposed to recover the location and sharpness of valuation thresholds from the density of assessed values around statutory breakpoints, treating the excess mass as a behavioural response to the marginal levy rate change. Because no observational data are available for the present analysis, the paper characterises the operating characteristics of the proposed design under a declared variance structure. A replication-based evaluation of the before-after-control-impact estimator was conducted across 2000 design cells, with between-cluster SD of 6.0, residual SD of 4.5, and an intraclass correlation of 0.64. The analysis indicates that 54 clusters are required to detect a 5 percentage point effect at 80% power. The contribution is a design protocol that links bunching detection to the institutional sequence of appeal and permit withdrawal, specifying the conditions under which threshold effects are identifiable and the cluster counts at which the design attains conventional power.