Rural development radio broadcast licensing fees and community listening-group maintenance in Tanzania: an instrumental-variable analysis of spectrum-allocation thresholds

Community listening groups are a long-standing infrastructure of rural development radio in Tanzania, yet their maintenance depends on broadcasters' capacity to sustain regional transmission, which in turn is shaped by the licensing fees broadcasters pay for spectrum. Because no observational data are available, the paper characterises the operating characteristics of the proposed design under a declared variance structure: between-cluster standard deviation of 6.0, 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 achieves 80 per cent power to detect a 5 percentage-point effect with 52 clusters.