Statistical validation of the CLARA Simplified Planning Tool Available to Purchase

The CLARA Simplified Planning Tool (CLARA-SPT) supports economic planning of water supply and sanitation system alternatives by applying life-cycle cost (LCC) principles. The cost functions used in the tool were developed based on standard designs, bills of quantities and a database of country-specific unit rates. In order to make reasonable economic comparison among system alternatives, the simulations of the tool should be able to predict costs of actual systems efficiently. In this paper, various statistical validation measures were employed to evaluate the simulation accuracy of the CLARA-SPT for eight water supply and nine sanitation technologies commonly implemented in Ethiopia. After evaluating the simulated outputs against observed cost data, appropriate corrective measures were introduced for technologies that did not replicate reality fairly. Costs of seven water supply and six sanitation technologies were able to be represented by the CLARA-SPT with good accuracy. Disinfection was however mimicked fairly. In addition, poor simulation accuracy was identified for three sanitation technologies (i.e. UDDT, Composting toilet and Faecal sludge collection). Therefore, the tool developers are advised to correct internal design assumptions of these three sanitation technologies to improve the simulation accuracy of the CLARA-SPT.