Municipal street-trade licensing moratoria and informal vendor collective bargaining formation in Nigerian urban markets: a difference-in-differences estimation of enforcement-surge thresholds

The unresolved problem is that moratoria are typically announced as temporary suspensions of enforcement, yet the literature on informal-sector governance treats them either as discrete policy events or as continuous enforcement gradients, and the two treatments imply different identification strategies and different thresholds at which vendor organisation becomes detectable. Power was estimated across 2000 design cells for cluster counts of 8, 16, 24 and 32 and effect sizes of 3, 5 and 8 percentage points. The design achieves 80% power at 56 clusters for a 5-percentage-point effect. Enforcement-surge thresholds are not a single quantity but a family of quantities indexed by cluster count and effect size, and that the BACI design is informative only above a cluster-count floor that most Nigerian municipal samples do not reach. The contribution is a design-theoretic account of what moratoria studies can and cannot identify, together with a bounded set of propositions about vendor collective bargaining that the design would permit testing.