Rural development cooperative warehouse receipt collateral and smallholder distress sales in Ethiopia: a regression-discontinuity analysis of warehouse certification thresholds

Warehouse receipt systems are promoted as a remedy for smallholder distress sales in Ethiopia, and a growing evaluation literature uses certification thresholds as regression-discontinuity instruments. No observational data are analysed. Instead, the operating characteristics of a before-after-control-impact estimator are characterised 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, across 2000 replications per design 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, that power falls below conventional thresholds at the smaller cluster counts, and that the minimum detectable effect declines steeply as clusters are added. The contribution is a design rule: threshold-based evaluations of warehouse certification in Ethiopia are underpowered at the cluster counts typically available, and the intraclass correlation of 0.64, not the certification rule itself, governs what such studies can establish.