Effects of measurement error on the strength of concentration-response relationships in aquatic toxicology.
The effect that measurement error of predictor variables has on regression inference is well known in the statistical literature. However, the influence of measurement error on the ability to quantify relationships between chemical stressors and biological responses has received little attention in ecotoxicology. We present a common data-collection scenario and demonstrate that the relationship between explanatory and response variables is consistently underestimated when measurement error is ignored. A straightforward extension of the regression calibration method is to use a nonparametric method to smooth the predictor variable with respect to another covariate (e.g., time) and using the smoothed predictor to estimate the response variable. We conducted a simulation study to compare the effectiveness of the proposed method to the naive analysis that ignores measurement error. We conclude that the method satisfactorily addresses the problem when measurement error is moderate to large, and does not result in a noticeable loss of power in the case where measurement error is absent.
Sonderegger
Derek L
DL
Department of Statistics, Colorado State University, Fort Collins, CO, USAGM26079. sondereg@stat.colostate.edu
Wang
Haonan
H
Huang
Yao
Y
Clements
William H
WH
D000818:Animals; D015982:Bias; D003120:Colorado; D003198:Computer Simulation; D003627:Data Interpretation, Statistical; D004175:Diptera / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D054750:Ecotoxicology; D004784:Environmental Monitoring / Q000706:statistics & numerical data*; D052918:Environmental Restoration and Remediation; D008018:Life Cycle Stages / Q000187:drug effects / Q000502:physiology; D019216:Metals, Heavy / Q000032:analysis / Q000633:toxicity*; D015233:Models, Statistical; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D018570:Risk Assessment; D045483:Rivers / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
D019216:Metals, Heavy; D014874:Water Pollutants, Chemical