A Randomised Field Trial for the Cost-Effectiveness Evaluation of Manufacturing Plant Systems in Tanzania

{ "background": "The selection of manufacturing plant systems in developing economies is often based on capital cost or theoretical efficiency, with limited empirical evidence on their real-world cost-effectiveness under operational constraints.", "purpose and objectives": "This study aimed to develop and apply a novel randomised field trial methodology to empirically evaluate the comparative cost-effectiveness of two prevalent structural and mechanical plant systems in a Tanzanian industrial context.", "methodology": "A pragmatic, parallel-group randomised field trial was conducted across multiple manufacturing sites. Plants were randomised to implement either a conventional reinforced concrete frame system or a prefabricated steel system. Cost-effectiveness was evaluated using a primary outcome of cost per unit of operational throughput over a defined period. The analysis employed a generalised linear model: ln(it) = \β0 + \β1 + \β2 Xit + \εᵢₜ, where X represents covariates, with inference based on cluster-robust standard errors.", "findings": "The prefabricated steel system demonstrated a statistically significant reduction in total cost per unit, with a mean difference of 18.7% (95% CI: 12.3% to 25.1%) compared to the conventional system. This result was robust to sensitivity analyses controlling for site variability and initial implementation delays.", "conclusion": "The randomised trial provides rigorous, field-based evidence that prefabricated structural systems can offer superior cost-effectiveness in the studied setting, challenging reliance on traditional construction methods.", "recommendations": "Project planners and structural engineers should consider prefabricated steel systems as a viable, cost-effective option for similar manufacturing plants. Further trials are recommended to assess long-term durability and adaptability.", "key words": "randomised controlled trial, industrial structures, cost-benefit analysis, prefabrication, developing economies, structural systems", "contribution statement": "This paper presents the first application of a randomised field trial methodology to compare structural plant systems