The creation of these two complex models was an ambitious undertaking. The
models allow forecasting of RN supply and demand to the year 2020 at both the
national and state levels. Nonetheless, major limitations of the models include:
• The two models are independent of each other. The NDM makes
projections without considering the potential supply of nurses and vice
versa.
• The capacity to refine and update the models is dependent on the
availability of reliable data and adequate resources.
• Parts of both models are static. For example, in the NSM, the probability
of cross-state migration is based on historical patterns and fails to
consider the current shortage of RNs in each state. The NDM has limited
ability to model substitution between types of nurses and between nurses
and other healthcare workers. The NDM also has limited ability to capture
the interaction of healthcare settings (e.g., home health as a viable
substitute for nursing home facilities), while other settings might be
complementary (e.g., increased use of outpatient services leads to
increased use of home health services).
• Accuracy of projections are reduced by a number of factors:
- The level of aggregation (e.g., national projections will likely be
more accurate than state projections).
- Sample size (e.g., larger states will likely be more accurate
compared to smaller states).
- The projection horizon (e.g., projections for the year 2005 will likely
be more accurate than the projections for 2020).
- The determinants of nursing supply and demand (i.e., currently
there is no consensus on what are the most important
determinants of nurse supply and demand, nor is there a
consensus on the future value of these determinants). |
