Because the monitoring data necessary for retrospective exposure assessment are lacking in most cases, assessors typically must rely on less exact methods to estimate historical exposure, such as interviews, questionnaires, documentation of occupational histories, centralized monitoring data for air and water pollutants, or construction of exposure scenarios (NRC 1991; Sexton et al. 1995b, 2004a).
Data from 2,445 subjects (51.7 % females) aged 18 to 65 years participating in a population-based cross-sectional study were assessed based on a standardized questionnaire and documentation of physical, biochemical and ultrasonographic findings.
Questionnaires and documentation analysis were conducted three months before IT introduction, in Febr.
The data are predominantly obtained by paper-based questionnaires and documentation sheets.
Questionnaires and documentation analysis were conducted three months before IT introduction and again in Dec. 2000 and in June 2001.
Structured questionnaires and documentation forms were used during the intervention period, and, for the delayed-intervention group only, during the observation period, identical for all hospitals (Table 3 ).
The main data collection comprises of paper-pencil questionnaires and documentation forms for chart reviews as well as telephone interviews with patients.
Structured questionnaires and documentation forms were used during the intervention period, and, for the delayed-intervention group only, during the observation period, identical for all hospitals (Table 3).> -wrap-foot> a This form differs slightly for the delayed intervention group and the immediate intervention group.
Still, there might have occurred an observation bias, since patients and GPs alike were made alert to specific aspects of care that they were asked about in the questionnaires and documentations.
