Statistical evaluation of exposure assessment strategies.
Appl Occup Environ Hyg 1991 Jun; 6(6):516-520
Three statistical evaluation techniques were proposed and discussed for two types of exposure assessment strategies, categorization of exposure and estimation of actual personal exposure levels. Exposure categorization included ordinal but nonquantitative groupings and quantitative exposure intervals. Estimates of actual exposure levels included job by year exposure matrices and exposure prediction models. Sources of uncertainty were discussed for ordinal classification, exposure matrices and exposure prediction models. The magnitude of error in exposure assessment could be estimated quantitatively for exposure matrices and exposure prediction models. Statistical evaluation methods discussed included sensitivity analysis, cross validation techniques and field techniques. These methods were discussed with particular reference to exposure prediction models. Sensitivity analysis identified which exposure factors had the maximum effect on exposure estimates and identified exposure factor combinations predictive of exposure levels out of any reasonable range. Cross validation used models developed for one data subset, with accuracy of the model evaluated using the other data subset. Field testing was useful when limited data were available for cross validation or when prediction models were not developed from measurement data. This method directly measured validity of an exposure assessment by actual measurement of current exposure levels. Field testing was the most generally applicable method but had disadvantages of greater expense and nonreplicability of historic conditions within current operations. Cross validation was the best technique for assessing prediction models based on measured exposures. The author concludes that the type of validation technique for an exposure assessment depends in part on the type of assessment methodology.
NIOSH-Publication; NIOSH-Author; NIOSH-Contract; Contract-91-38661; Humans; Occupational-exposure; Exposure-levels; Statistical-analysis; Analytical-methods; Epidemiology; Analytical-models
Applied Occupational and Environmental Hygiene