"background": "Power-distribution losses in many developing nations remain persistently high, undermining grid reliability and economic development. In Tanzania, technical and non-technical losses have historically constrained the efficiency of the national grid, yet comprehensive methodological evaluations of system-wide equipment performance are scarce. ", "purpose and objectives": "This case study aims to methodologically evaluate the efficiency of Tanzania's power-distribution equipment systems. Its objectives are to develop a robust analytical framework for quantifying efficiency gains and to identify the principal technical factors driving performance variability across the network. ", "methodology": "A multilevel regression analysis was applied to a longitudinal, system-level dataset comprising technical performance indicators. The core statistical model is specified as y{ij = \0 + \1Xij + uj + eij, where yij is the efficiency metric for transformer i in region j, Xij denotes a vector of equipment-level covariates, uj represents regional random effects, and eij is the residual error. Inference was based on robust standard errors. ", "findings": "The analysis indicates a statistically significant positive relationship between targeted equipment upgrades and systemic efficiency. A key concrete result is that the modernisation of ageing circuit breakers and switchgear was associated with an estimated 7. 5 percentage point reduction in technical losses (95% CI: 5. 2 to 9. 8). Regional heterogeneity accounted for approximately 22% of the total variance in efficiency outcomes. ", "conclusion": "The methodological approach confirms that multilevel modelling effectively captures the hierarchical structure of distribution network data. It provides a validated framework for isolating the impact of specific equipment interventions from broader regional operational disparities. ", "recommendations": "Utilities should adopt hierarchical modelling for future investment planning and performance benchmarking. Priority should be given to programmes targeting the identified high-impact equipment categories, with monitoring systems adapted to collect data at appropriate hierarchical levels. ", "key words": "power distribution,
Mwinyi et al. (Thu,) studied this question.