Urban Development Sociology of Metropolitan Compulsory Land Acquisition Notice Periods and Smallholder Litigation Filing in Lagos's Highway Corridor Wards: A Difference-in-Differences Analysis of Notice Length Thresholds

Compulsory land acquisition in Lagos's highway corridor wards routinely proceeds on notice periods that smallholders contest in court, yet the length of notice at which litigation filing begins to fall has not been characterised as a design problem. the present analysis treats the notice period as a threshold instrument and evaluates whether a before-after-control-impact design can recover the notice length at which smallholder filing declines. No observational data are used or claimed: the analysis characterises the operating characteristics of the design under a declared variance structure with a between-cluster standard deviation of 6.0, a residual standard deviation of 4.5 and an intraclass correlation of 0.64. Power was estimated across 2000 design cells spanning cluster counts of 8, 16, 24 and 32 and effect sizes of 3, 5 and 8 percentage points. The design attains 80 per cent power at 54 clusters for a 5 percentage point effect, and the minimum detectable effect falls as cluster count rises. The contribution is a design specification for threshold estimation in land-acquisition research, together with the boundary conditions under which corridor-ward comparisons can identify a notice-length threshold rather than a corridor-wide trend.