Ecology

Investigators at Aquatic Ecology Laboratory Detail Research in Environmental Metrics

  2012 JUN 29 (VerticalNews) -- By a News Reporter-Staff News Editor at Ecology, Environment & Conservation -- Current study results on Environmental Metrics have been published. According to news reporting from Kearneysville, West Virginia, by VerticalNews journalists, researchers stated "A main benefit from taking a systematic sample is the ease of implementation when field sampling. However, it is not uncommon for a researcher to sample only one primary sampling unit (PSU) but to assume that the secondary sampling units (SSUs) were selected by simple random sampling to obtain a variance estimate."

  The news correspondents obtained a quote from the research by the authors from Aquatic Ecology Laboratory, "To obtain an unbiased estimator of variance for conventional or adaptive systematic sampling, it is necessary to sample? >?1 PSUs, and this can marginally increase cost and complicate implementation. We show that it is possible to obtain an unbiased estimate of variance if the researcher takes only a single PSU and one or more SSUs. Although this is no longer a true systematic sample, such a design retains much of the simplicity of sampling a single PSU and allows for a valid variance estimate. This paper introduces three new sampling strategies stemming from systematic adaptive cluster sampling and the Raj estimator. The new sampling designs will be referred to as partial systematic adaptive cluster sampling. The sampling strategies are investigated in a simulation study that utilizes distance traveled as a measure of cost when comparing sampling strategies."

  According to the news reporters, the researchers concluded: "When only a single PSU can be sampled because of cost or logistics concerns, we recommend also sampling one or more SSUs to obtain an unbiased estimate of variance."

  For more information on this research see: Partial systematic adaptive cluster sampling. Environmetrics, 2012;23(4):306-316. Environmetrics can be contacted at: Wiley-Blackwell, 111 River St, Hoboken 07030-5774, NJ, USA. (Wiley-Blackwell - www.wiley.com/; Environmetrics - onlinelibrary.wiley.com/journal/10.1002/(ISSN)1099-095X)

  Our news journalists report that additional information may be obtained by contacting A.L. Dryver, USGS Leetown Sci Center, Aquat Ecol Lab, Kearneysville, WV 25430, United States.

  Keywords for this news article include: Kearneysville, West Virginia, United States, Environmental Metrics, North and Central America

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