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RANKED SET SAMPLING FOR ECOLOGICAL RESEARCH: ACCOUNTING FOR THE TOTAL COSTS OF SAMPLING
Mode, N. A., L. L. Conquest, AND D. A. Marker. RANKED SET SAMPLING FOR ECOLOGICAL RESEARCH: ACCOUNTING FOR THE TOTAL COSTS OF SAMPLING. ENVIRONMETRICS. John Wiley & Sons, Ltd., Indianapolis, IN, 10:179-194, (1999).
Researchers aim to design environmental studies that optimize precision and allow for generalization of results, while keeping the costs of associated field and laboratory work at a reasonable level. Ranked set sampling is one method to potentially increase precision and reduce costs by using "rough but cheap" quantitative or qualitative information to obtain a more representative sample before the real, more expensive sampling is done. In this report, we investigate under what conditions ranked set sampling becomes a cost-effective sampling method for ecological and environmental field studies where the "rough but cheap" measurement has a cost. Ratios of measuring to ranking costs necessary for ranked set sampling to be as cost effective as simple random sampling, for a common precision, are presented or known distributions with and without ranking error. Cost ratios are also presented for a real data set consisting of visually estimated and physically measured stream habitat areas. Results provide specific guidelines for when ranked set sampling is appropriate, and cost effective, for ecological and environmental field sampling.