Advanced specialty training is the sine qua non of physician fellowship in Australia and New Zealand. The training curriculum and foci are constantly changing owing to advances in medicine, evolving workforce supply and demand with inter-speciality crossover, and growing population and associated demographic shifts. Ideally, workforce equilibrium provides a robust healthcare system when the supply equals the demand. However, workforce prediction is an unavoidably imprecise science.Lag times between entering medical school and ultimately practising in a specialty are long. Although workforce input from advanced training tends to be constant with predictable trends, influxes from overseas trained physicians and the input of physicians via a grandfather clause (who practise subspecialties but are not listed within that specialty with the Royal Australasian College of Physicians (RACP)) add to numbers in a manner that is difficult to predict or capture reliably. Furthermore, specialists move overseas, reduce hours for personal responsibilities (e.g. aged parents, maternity leave) or undertake other important, but nonclinical, vocational roles, such as research and academia. Last, there is the constant, yet unpredictable, attrition from retirement. Layering over this is the service delivery requirements of an ageing population and geographical distribution of service delivery needs trying to mesh with a generally metropolitan heavy specialty workforce. States and territories fund public posts and add to the complexity of aligning workforce to service needs.Trying to reach the workforce specialty nirvana of 'service and research delivery' equalling 'service needs', requires robust attention to data collection, preferably by a national body. This aspect, although imperfect, has greatly strengthened over the years with both the RACP and Australian Health Practitioner Regulation Agency (AHPRA) collecting data with the reader recommended to review annual RACP member statistics and insight reports. According to AHPRA annual reports, the number of physicians continues to increase in Australia and New Zealand at a rate of 4-6% per year, with a 6.6% increase between 2019 and 2020 incorporating a greater rate of increase in female compared with male physicians. Similar patterns were observed in nephrology, with a 6.2% increase between 2019 and 2020. 1 The consequences of an increased number of physicians and gender shift are uncertain. The workforce data requires analysis of trends in vocational planning and satisfaction to