Table 1 Criteria for estimating needs-based supply of physicians and underlying questions

1. Conceptual framework

1.1 Selection and justification of needs indicators

Is the selection of indicators theoretically well-founded and empirically supported for the respective context of the analysis?

1.2 Relationship between supply and need

Is the conceptual dependency of indicators of need on supply

• in general,

• regarding unmet need/lack of physicians or

• regarding overuse/oversupply

examined and, if possible, accounted for in the framework?

2. Data basis

2.1 External validity

Is the population for which providers are to be planned and the population from which data are used identical or representative?

2.2 Internal validity

Does the observed data accurately measure the indicators of interest?

2.3 Timeliness and availability

Is the timeliness of data and availability of data sources reported, and considered with respect to the intended planning horizon?

3. Modelling and translation into physician capacity

3.1 Transformation into provider requirements

Is the estimated need for healthcare related to some measure of provider productivity to transfer the estimated service requirement to physician capacities?

3.2 Model selection and validation

Is the statistical model appropriate and well-founded, and were the validity and the robustness of the findings established?

3.3 Level of analysis

Was the level of analysis defined and discussed regarding the potential for ecological errors?

4. Integration of future trends and developments

4.1 Projection variables

Are projection variables identified that can be modelled according to future changes in population need for healthcare?

4.2 Planning horizon

Was the chosen planning horizon justified appropriately with respect to future changes?