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Your search keyword '"critical effect size"' showing total 3 results
Start Over Descriptor "critical effect size" Topic analysis of variance
3 results on '"critical effect size"'

1. A REVIEW OF POTENTIAL METHODS OF DETERMINING CRITICAL EFFECT SIZE FOR DESIGNING ENVIRONMENTAL MONITORING PROGRAMS.

Author

Munkittrick, Kelly R., Arens, Collin J., Lowell, Richard B., and Kaminski, Greg P.

Subjects
*ENVIRONMENTAL monitoring, *ENVIRONMENTAL engineering, *POLLUTION measurement, *POLLUTION monitoring, *FIELDWORK (Educational method), *DISTRIBUTION (Probability theory), *SUSTAINABLE development, *ENVIRONMENTAL protection, *ANALYSIS of variance
Abstract

The effective design of field studies requires that sample size requirements be estimated for important endpoints before conducting assessments. This a priori calculation of sample size requires initial estimates for the variability of the endpoints of interest, decisions regarding significance levels and the power desired, and identification of an effect size to be detected. Although many programs have called for use of critical effect sizes (CES) in the design of monitoring programs, few attempts have been made to define them. This paper reviews approaches that have been or could be used to set specific CES. The ideal method for setting CES would be to define the level of protection that prevents ecologically relevant impacts and to set a warning level of change that would be more sensitive than that CES level to provide a margin of safety; however, few examples of this approach being applied exist. Program-specific CES could be developed through the use of numbers based on regulatory or detection limits, a number defined through stakeholder negotiation, estimates of the ranges of reference data, or calculation from the distribution of data using frequency plots or multivariate techniques. The CES that have been defined often are consistent with a CES of approximately 25%, or two standard deviations, for many biological or ecological monitoring endpoints, and this value appears to be reasonable for use in a wide variety of monitoring programs and with a wide variety of endpoints. [ABSTRACT FROM AUTHOR]

Published
2009
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2. Within-animal variation as an indication of the minimal magnitude of the critical effect size for continuous toxicological parameters applicable in the benchmark dose approach

Author

Monique Rennen, Marco J Appel, Jan Telman, Cees de Heer, Susan Dekkers, and TNO Industrie en Techniek TNO Kwaliteit van Leven

Subjects
Male, Magnitude (mathematics), Review, Adverse effect, Residual, Toxicology, Poisons, Clinical chemistry, Statistics, Analysis of variance, Safety, Risk, Reliability and Quality, Critical effect size (CES), Rodent, Data reduction, Circadian rhythm, Estimation theory, Breaking point, Biodiversity, Hematology, Temporal variation, Benchmarking, Variation (linguistics), Error analysis, Toxicological parameters, Data Interpretation, Statistical, Variance analysis, Female, Food and Chemical Risk Analysis, Benchmark approach, Effect size, Biology, Intraspecific variation, Risk Assessment, Dogs, Physiology (medical), Parameter estimation, Animalia, Animals, Animal experiment, Rats, Wistar, Analysis of Variance, Observational error, Toxicity, Dose-Response Relationship, Drug, Adverse effects, Data interpretation, Nonhuman, Sex difference, Rats, Within-animal variation, Toxicity testing, Rat, Critical effect size, Controlled study
Abstract

In this study, the within-animal variation in routinely studied continuous toxicological parameters was estimated from temporal fluctuations in individual healthy nonexposed animals. Assuming that these fluctuations are nonadverse, this within-animal variation may be indicative of the minimal magnitude of the critical effect size (CES). The CES is defined as the breaking point between adverse and nonadverse changes in a continuous toxicological parameter, at the level of the individual organism. The total variation in the data from individual nonexposed animals was divided in variation parts due to known factors (differences in sex, animal, and day) and a residual variation, by means of analysis of variance. Using the residual variation and the estimated analytical measurement error of a toxicological parameter, the within-animal variation can be estimated. The data showed within-animal variations ranging between 0.6% and 34% for different clinical chemistry and hematological parameters in 90-day rat studies. This indicates that different (minimal) CES values may be applicable for different parameters. © 2006 Society for Risk Analysis.

Published
2006

3. Within-animal variation as an indication of the minimal magnitude of the critical effect size for continuous toxicological parameters applicable in the benchmark dose approach

Subjects
Male, Data Interpretation, Food and Chemical Risk Analysis, Benchmark approach, Wistar, Review, Effect size, Adverse effect, Intraspecific variation, Toxicology, Risk Assessment, Poisons, Clinical chemistry, Dose-Response Relationship, Dogs, Parameter estimation, Animals, Animalia, Animal experiment, Analysis of variance, Biology, Critical effect size (CES), Rodent, Data reduction, Toxicity, Adverse effects, Circadian rhythm, Biodiversity, Hematology, Statistical, Nonhuman, Sex difference, Temporal variation, Rats, Benchmarking, Within-animal variation, Error analysis, Toxicological parameters, Variance analysis, Toxicity testing, Rat, Female, Drug, Critical effect size, Controlled study
Abstract

In this study, the within-animal variation in routinely studied continuous toxicological parameters was estimated from temporal fluctuations in individual healthy nonexposed animals. Assuming that these fluctuations are nonadverse, this within-animal variation may be indicative of the minimal magnitude of the critical effect size (CES). The CES is defined as the breaking point between adverse and nonadverse changes in a continuous toxicological parameter, at the level of the individual organism. The total variation in the data from individual nonexposed animals was divided in variation parts due to known factors (differences in sex, animal, and day) and a residual variation, by means of analysis of variance. Using the residual variation and the estimated analytical measurement error of a toxicological parameter, the within-animal variation can be estimated. The data showed within-animal variations ranging between 0.6% and 34% for different clinical chemistry and hematological parameters in 90-day rat studies. This indicates that different (minimal) CES values may be applicable for different parameters. © 2006 Society for Risk Analysis.

Published
2006

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