title: Limitations on the uses of multimedia exposure measurements for multipathway exposure assessment--Part II: Effects of missing data and imprecision.
abstract: Multimedia data from two probability-based exposure studies were investigated in terms of how missing data and measurement-error imprecision affected estimation of population parameters and associations. Missing data resulted mainly from individuals'refusing to participate in certain measurement activities, rather than from field or laboratory problems; it suggests that future studies should focus on methods for maximizing participation rates. Measurement error variances computed from duplicate-sample data were small relative to the inherent variation in the populations; consequently, adjustments in nonparametric percentile estimates to account for measurement imprecision were small. Methods of adjustment based on lognormality assumptions, however, appeared to perform poorly.
authors.affiliation: RTI International, PO Box 12194, 3040 Cornwallis Road, Research Triangle Park, NC 27709, USA. clayton@rti.org
authors.forename: C Andrew
authors.initials: CA
authors.lastname: Clayton
authors.forename: Larry
authors.initials: L
authors.lastname: Michael
authors.forename: Edo D
authors.initials: ED
authors.lastname: Pellizzari
authors.forename: James J
authors.initials: JJ
authors.lastname: Quackenboss
mesh_terms: D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure; D004812:Epidemiologic Methods; D006801:Humans; D006838:Hydrocarbons / Q000032:analysis*; D008670:Metals / Q000032:analysis*; D015233:Models, Statistical; D019212:Multimedia; D010755:Organophosphates / Q000032:analysis*; D011159:Population Surveillance / Q000379:methods; D014481:United States; D014484:United States Environmental Protection Agency
chemical_list: D006838:Hydrocarbons; D008670:Metals; D010755:Organophosphates