{ "background": "Chronic inefficiencies in power-distribution networks, characterised by high technical and commercial losses, impede reliable electricity supply and economic growth. In Ghana, ageing infrastructure and operational challenges necessitate robust analytical frameworks to evaluate equipment performance and inform capital investment policy.", "purpose and objectives": "This policy analysis develops and applies a novel Bayesian hierarchical model to quantify efficiency gains within the nation's power-distribution equipment systems. It aims to provide a methodological framework for assessing past performance and projecting future efficiency trajectories under different policy scenarios.", "methodology": "A Bayesian hierarchical model was constructed, integrating equipment-level data across multiple regions. The core model structure is $y{it} \\sim \\text{Normal}(\\alphai + \\betat, \\sigma^2)$, with $\\alphai \\sim \\text{Normal}(\\mu{\\alpha}, \\tau{\\alpha}^2)$ representing region-specific random effects and $\\beta_t$ capturing temporal trends. Posterior distributions were estimated using Markov chain Monte Carlo simulation, with inferences based on 95% credible intervals.", "findings": "The model indicates a positive but heterogeneous trend in technical efficiency across regions, with posterior probability exceeding 0.95 that the national aggregate efficiency gain will be between 12% and 18% over the analysis period. Transformer performance showed the most significant improvement, whereas switchgear systems exhibited greater regional variability and slower progress.", "conclusion": "The Bayesian hierarchical approach provides a statistically robust framework for policy analysis, effectively quantifying uncertainty in efficiency measurements. It demonstrates that while overall gains are achievable, targeted regional interventions are required due to persistent performance disparities.", "recommendations": "Policy should prioritise investment in data-collection systems to feed such models. Regulatory frameworks must incentivise efficiency improvements in lagging equipment categories and regions. Capital expenditure planning should integrate probabilistic forecasts from hierarchical models to optimise resource allocation.", "key words": "Bayesian inference, hierarchical modelling, distribution losses, power infrastructure, probabilistic forecasting, policy evaluation", "contribution