Table 1 Overview of forecasting approaches

Supply model

To project the number of physicians required to match the current services given the likely changes in the profession (age, feminization, etc...)

• Can project physician numbers at 10–15 years with accuracy (?)

• Perpetuates current physician-to-population ratio assumed to be adequate

• Does not consider the evolution of the care demand

USA [13–17]

Australia [18]*

Nova Scotia, Canada [21]

Demand model

To project the number of physicians required to match the current services given the likely changes in the demand (mainly population ageing and GDP growth)

• Can anticipate changes in health practices (e.g. new surgical techniques or drugs) and in the health system

• Perpetuates current utilization of services (SID, inappropriate services not addressed)

• Assumes that MDs are the main actors and that any care is useful

• Does not consider the demand for non curative services (prevention, research) and future trends

• Requires huge amounts of data

USA [14, 31–33]

Canada [10, 11, 26]

Needs-based model

To project the number of physicians required to provide appropriate health care to the future population

• Rely on a normative approach, i.e. can avoid the perpetuation of existing inequities and inefficiencies

• Can include unmet needs in the estimation process

• Requires detailed knowledge of the efficacy of individual medical services for specific conditions

• Does not account for technological developments and changes in the organization of health services

• The assumption that health care resources will be used in accordance with relative levels of need is not necessarily verified

• Ignores the question of the efficiency in the allocation of resources between different sectors of the society

USA [33, 36]

Ontario, Canada [10, 11, 50]

Australia [30]

Benchmarking

To refer to a current best estimate of a reasonable physician workforce

• Realistic

• Is valid only if communities and health plans are comparable, i.e. adjusted for key demographic, health and health system parameters

• Often does not document the extrapolation methodology sufficiently (e.g. unclear criteria for selecting the reference)

USA [13, 33, 37, 40]

Australia [30, 39]