Rationale: Many nations are facing shortages of Registered Nurses (RNs) and other health professionals. Within the United States, the U.S. Bureau of the Health Professions has conducted surveys of RNs since 1977, and has periodically published forecasts of the supply, demand, and shortage of RNs. The state of California also has conducted surveys of RNs and developed its own shortages. The ability of statistically-based surveys, and econometric and stock-flow forecasting models to predict future health workforce supply and demand needs close examination. Objectives: This paper critically assesses strategies to forecast supply and demand for health professionals, using the RN workforce as an example. Methodology: First, we review methods for obtaining data about the RN workforce, from surveys and administrative data. We compare the patterns of employment and demographics identified in different datasets and identify potential causes for discrepancies. Second, we review methods for forecasting the supply of RNs. Most approaches to estimating future supply focus on stock-and-flow models. Third, we review methods for forecasting the demand for RNs. Here, there is substantial divergence in the literature. Some researchers use RN-per-capita ratios as a proxy for demand. Others create simple forecasts from current RN-per-patient ratios and forecasts of future hospitalization rates. A third approach involves developing econometric models. The results of these three strategies will be compared using California as a case study. We then will examine how forecasting strategies can be applied to regions within a nation or other jurisdiction, again using California as an example. Finally, we will compare forecasts that have been published over time, to learn how accurate these forecasts have been. The findings of this assessment will be discussed in the context of general development of health workforce forecasting models. Results: A careful examination of health workforce forecasting strategies, with a focus on the economic factors that affect supply and demand, will help states, provinces, cities, and nations better assess whether and how to plan for future health workforce needs. The US government has completed the 2004 National Sample Survey of RNs, and data will be released soon (the author has a pre-release version of the data). US forecasts are now being updated. The California government has the 2006 Survey of California RNs in the field now, and a final report, with forecasts, is due to the government before May 2007
