Sampling and weighting of the Austrian Psychiatric Prevalence Survey (APPS).

Mental disorders are common and have severe consequences for the patients, their relatives, and society. Mental health care planning requires precise knowledge of the prevalence of psychiatric disorders and details regarding the provided treatment. Because administrative data lack information on persons not in contact with health services, we need epidemiologic studies delivering nationwide information on the prevalence of psychiatric disorders. This requirement induces the need for adequate sampling procedures to collect reliable data, allowing for accurate estimations of mental health care needs, over- and underprovision. This is the purpose of the Austrian Psychiatric Prevalence Survey (APPS).The present technical report describes the exact procedure how a nationwide sample has been drawn, adopting a stratified cluster sampling scheme. Because such a complex sampling procedure requires an adequate weighting to obtain unbiased population estimates, this report also contains the exact steps to calculate the corresponding weights. This way, the report not only fosters the full disclosure of the sampling strategy of the APPS, it may also serve as a best practice example for similar endeavours.