Medicare Local catchments
Medicare Locals are primary health care organisations that plan and fund health services in communities across Australia. The network of 61 Medicare Locals across Australia help to ensure patients can access the care they need, particularly when a variety of health workers are involved in providing treatments. A Medicare Local catchment is a specific geographic area for which a Medicare Local has responsibility. For the report, statistical information is presented using the boundaries of Medicare Local catchments as released by the Department of Health.
Geographic correspondences (sometimes referred to as concordances or mapping files) can be used where the location information in an original survey, census or administrative data is not available at the geographic area required for analysis and reporting. Geographic correspondences are a mathematical method for reassigning data from one geographic area (for example a postcode of a patient’s address in a Medicare enrolment record) to a new geographic area (for example Medicare Local catchment).
In 2012, the Authority commissioned the Australian Bureau of Statistics (ABS) to compile several correspondences to convert data from defined geographic levels to Medicare Local catchment level using Medicare Local level boundaries and names that were available at the time.
Measures of GP care in the BEACH dataset are presented in the report by Medicare Local catchment, based on the postcode of the primary GP practice provided by the participating GP.
GP care statistics in this report were compiled by applying geographic concordances to the BEACH aggregate statistics at the current postcode of the primary practice of the participating GP.
Assignment of GP practices in the BEACH data to Medicare Local catchments
In the BEACH dataset participating GPs provide the postcode of their primary practice as well as a mailing address to the BEACH data custodian, the Family Medicine Research Centre, the University of Sydney for the purpose of mailing the paperbased survey forms. The allocation of GPs to Medicare Local catchments for these analyses were completed by the Family Medicine Research Centre according to rules of confidentiality.
For the majority of GPs included in this analysis, the postcode for the GP’s primary general practice and their Medicare Local catchment had a one-to-one fit, with the entire postcode falling within the boundaries of one Medicare Local catchment. For these GPs, the Medicare Local catchment was assigned using the postcode for their primary practice only.
For those GPs whose primary general practice postcode crossed two or more Medicare Local catchment boundaries, the mailing address was checked. If the postcode of the primary practice and the postcode of the mailing address matched, the Medicare Local was assigned by entering the mailing address into the Medicare Local finder on the Medicare Local website (www.medicarelocals.gov.au) – for updated information, see Medicare Local in glossary.
However, a small number of GPs (about 1%) had a primary general practice postcode that did not match the postcode of the mailing address. These GPs were assigned to the Medicare Local catchment containing the majority of the population of that postcode according to ABS estimated resident population figures.
Assignment of MBS data to Medicare Local catchments
To determine the percentage of people who visit the GP who have a chronic condition, MBS claims data were used to weight the GP consultations to the population that attended the GP (described above).
In compiling MBS statistics on the number of patients and number of associated GP consultations by sex and age range, the number of GP attendances for each patient was determined by the GP’s practice postcode. For a patient attending a general practice in a postcode with boundaries completely contained in one Medicare Local catchment, all GP consultations for the patient in that postcode were allocated to that Medicare Local catchment. For a postcode with boundaries that cross multiple Medicare Local catchments, the number of GP consultations in the postcode was proportionally assigned based on the proportion of the population in the postcode in each Medicare Local catchment.
Having determined the number of factored GP consultations for each patient at Medicare Local catchment level, if the factored number of GP attendances for a patient was greater than or equal to 0.5 in the Medicare Local catchment, the patient count was set to ‘1’, otherwise the patient count was set to ‘0’. Patients who visited GPs in more than one Medicare Local catchment were counted as ‘1’ patient in each catchment, provided the patient had 0.5 or more of a factored GP consultation in each Medicare Local catchment.
The age range and sex for each patient was determined from the last Medicare service of any type (not just GP attendances) for the patient, processed by the Department of Human Services.