Discussion of 'Cost Models for Water Supply Distribution Systems' by Robert M. Clark, Mano Sivaganesan, Ari Selvakumar, and Virendra Sethi

摘要

This article has the appearance of being technically sound and a contribution to. new knowledge, but unfortunately it has many flaws. Part of the purpose for writing this discussion is to plea for more rigor in papers whose content is mainly statistical. The stated purpose of the paper is to present mathematical models that can be used for estimating the costs of water distribution system components. It follows that confidence in using these models, and therefore confidence that they will produce accurate estimates, lies at the heart of this paper. The authors clearly state that the intended use of their models is for making preliminary cost estimates; hence the models must be judged against that objective. If the models are flawed, if their estimates are not accurate for the intended purpose, then the usefulness of the paper is compromised. From the outset, the authors raise expectations in their readers for a rigorous and defensible analysis. Regrettably, I find little basis for confidence in what they report.