Rural development cooperative land-lease renewal ballots and tenant-farmer investment in soil conservation in Ghana: a regression-discontinuity analysis of lease-term thresholds

Regression-discontinuity designs have become the default strategy for identifying how lease-term thresholds shape tenant-farmer investment in soil conservation, yet the credibility of that strategy depends on design features that are rarely examined before fieldwork begins. the present analysis treats the proposed Ghanaian cooperative land-lease renewal ballot as a design problem rather than a data problem. It specifies a before-after-control-impact estimator for the threshold effect, declares a 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, and characterises the operating characteristics of the design across 2000 replications per cell for cluster counts of 8, 16, 24 and 32 and effects of 3, 5 and 8 percentage points.54 clusters are required to detect a 5-percentage-point effect at 80 per cent power under this variance structure, that the minimum detectable effect falls steeply as clusters are added, and that the estimator's interval coverage is sensitive to the ratio of between-cluster to residual variance. The contribution is a pre-fieldwork design appraisal that specifies the cluster count, effect range and variance assumptions a credible threshold study of conservation investment would need, and that identifies the conditions under which the ballot-threshold design would fail to distinguish a real behavioural response from cluster-level heterogeneity.