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Reliability of retrospective chlorophenol exposure estimates over five decades
Author(s) -
Teschke Kay,
Marion Stephen A.,
Ostry Aleck,
Hertzman Clyde,
Hershler Ruth,
DimichWard Helen,
Kelly Shona
Publication year - 1996
Publication title -
american journal of industrial medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.7
H-Index - 104
eISSN - 1097-0274
pISSN - 0271-3586
DOI - 10.1002/(sici)1097-0274(199611)30:5<616::aid-ajim10>3.0.co;2-6
Subject(s) - intraclass correlation , medicine , reliability (semiconductor) , statistics , demography , cohort , environmental health , psychometrics , mathematics , clinical psychology , power (physics) , physics , quantum mechanics , sociology
For a cohort study of chlorophenate‐exposed sawmill workers, historical exposures from the 1940s to the 1980s were estimated by teams of 9–20 employees (each interviewed individually). The mill histories were divided into eras when jobs and exposures were relatively stable. Raters with at least 5 years of work experience in an era were asked to estimate the frequency and duration of exposure for each job in the mill. Reliability measures for these estimates were calculated for each of the 39 mill and time period combinations, using the individual intraclass correlation coefficient (ICC ind ) to assess agreement between raters and the group intraclass correlation coefficient (ICC group ) to assess the stability of the mean estimates of exposure. ICC ind were low, with means that increased from 0.24 to 0.35 over the five decades. ICC group were considerably higher (means increasing from 0.78 to 0.88 over time), indicating that the number of raters used in this study was sufficient to produce stable average estimates of exposure throughout the study period. These data confirm the intuitive expectation that reliability of exposure estimates decreases when reconstruction of conditions in the distant past is required, and therefore that the random component of exposure misclassification is a greater threat to validity in these earlier time periods. © 1996 Wiley‐Liss, Inc.