MEDICAL SURVEY DESIGN
The 2001/2 Medical Survey is despatched in two stages and is used to produce two publications. Practitioners are the statistical unit for the first stage of the survey while the medical and administrative services businesses for which the practitioners work form the statistical unit for the second stage despatch.
The first stage involves selection of a random sample of practitioners from a list of practitioners obtained from the Department of Health and Aged Care's Medicare Provider File. The first stage despatch, which occurred in February, asks the selected practitioners to provide details about themselves (such as hours worked, main field of work, number of private patient contacts in an average week) as well as details of the medical practices they work for (such as name, address, ABN, main income earning activity of business).
A second stage despatch will occur in August 2002 and will consist of the selection of all in-scope practices identified by the practitioners selected in the first stage despatch. In addition, a small number of pathology labs will be selected from a frame created from a number of sources. The second stage despatch will seek detailed financial and employment data from the medical practices. Business details collected from practitioners in the first stage despatch will be used in the identification and removal of duplicate practices prior to the second stage being despatched.
The Medicare Provider file is used as the frame for the first stage survey instead of the ABS Business Register because:
- The ABS Business Register does not have a list of individual practitioners;
- The general structure of medical 'practices' is a non-standard unit concept. 'Practices' are formed from the combined operations of medical businesses and their associated administrative services businesses, with the latter generally classified to non-medical industry classifications (i.e. ANZSICs). The practice represents the medical 'industry' unit of interest for users.
A survey of the private medical practice industry was previously conducted in respect of 1994-95. A few changes have occurred since the last survey including:
- The ABS Business Register does not allow for the stratification of specialists into the required individual specialties (eg. anaesthesia, paediatrics, dermatology, pathology, surgery, psychiatry).
- the requirement to output estimates for General Practitioners by RRMA (Remote, Rural and Metropolitan Areas classification).
The first stage sample is a stratified simple random sample. In the second stage, all practices identified are completely enumerated. It should be noted however that the sample design doesn't strictly meet the definition of a two stage design because the first stage sampling units (practitioners) are a subset of the second stage sampling units (practices). Also, conventional two stage formulae don't hold due to the fact that is possible to have a doctor work in several practices, and a practice can have several doctors working in it.
The 94/95 Medical survey dataset was used as design data in the sample design. Optimal allocation was used to determine the sample sizes required for both stages of the survey, taking account of separate constraints and design variables for the two stages.
The Stage 1 despatch will be sent to 3,100 practitioners from of a population of over 37,000. The second stage despatch is expected to be sent to approximately 4,000 businesses.
For more information please contact Adam Thomas on (03) 9615 7406
- the recent emergence of corporates in the private medical practice industry (i.e. non-medical businesses managing private medical practices).