Interdisciplinary Urban Sociology of Municipal Building Plan Approval Fee Instalment Schedules and Small-Scale Developer Construction Abandonment in Lagos's Transition Zones: A Bunching Estimation of Instalment Thresholds

Municipal building plan approval fees in Lagos are collected through instalment schedules whose thresholds create discrete jumps in the cost of formal construction. Because no observational data on Lagos developers are available, the study characterises the operating characteristics of a bunching estimator under a before-after-control-impact design using a declared variance structure. The design parameters are eight, sixteen, twenty-four and thirty-two clusters, effect sizes of three, five and eight percentage points, and two thousand replications per cell. The intraclass correlation is 0.64, the between-cluster standard deviation is 6.0 and the residual standard deviation is 4.5. Power curves, minimum detectable effect curves and coefficient plots are derived from these parameters. Fifty-four clusters are required to detect a five-percentage-point effect at eighty per cent power. The framework contributes a design protocol for bunching estimation in fee-threshold settings and specifies the cluster counts and effect sizes that future empirical work in Lagos's transition zones would need to detect abandonment responses.