External quality assurance in the German Health Interview and Examination Survey for Children and Adolescents (KiGGS).: Procedure and results

The results of the German Health Interview and Examination Survey for Children and Adolescents (KiGGS) of the Robert Koch Institute (RKI) will be of great importance for health policy and research. Therefore, in this study internal quality assurance was supplemented by an external quality assurance which was carried out by the institute of epidemiology at the GSF National Research Center for Environment and Health. The subjects were the interviewer training, sampling and response, field work and data management. External quality assurance was defined as 'an audit of internal quality assurance measures and systematic observation and spot checks to ensure quality requirements were fulfilled'. The requirements followed the manual of operation and the recognized epidemiologic standards and guidelines. For the different subjects, tests and detailed check-lists were developed and used. The quality requirements were fulfilled: The field work was performed with high quality and remarkable engagement over the whole time from May 2003 to May 2006, which resulted in high response and data quality. An extensive, efficient quality management system was in place for the data management.