In Figure III.1 we start with retention rates in primary care HPSAs by years elapsed since separation from service (for participants) and by years since start year (for non-participants).
Using data from the first analytic dataset, we find that about 82% of the NHSC participants serve in primary care HPSAs one year after completion of their NHSC service. More than half of participants who are still in primary care HPSAs one year after separation are actually in the same county as the one in which they served while in service (i.e., 49% of participants). There is a fairly steep decline in the retention rate in years 2 and 3 after separation (by about 7 and 3 percentage points, respectively), followed by a leveling off thereafter.
Focusing on non-participants, we note that their retention rates in primary care HPSAs are always higher than the retention rates of participants, both in terms of retention in the same HPSA as well as in terms of retention in a different HPSA. Their retention also drops after we first observe them in the data (their ‘start’ year), but in contrast with participants the move rate out of HPSAs is relatively constant over time. One year after we first observe non-participants in HPSAs, 95% of them are still in HPSAs. Moreover, a very large fraction of them (91% of all non-participants) remain in the same HPSAs where they were first observed. The retention rates in any HPSAs decline by about 3-4 percentage points every year thereafter, while the retention rates in the same HPSA decline at a slightly faster rate (about 5-6 percentage points per year). These rates indicate that once non-participant providers serve in a HPSA, they tend to remain in those areas, and to some extent they migrate from one HPSA to another.
Figure III. 1: Retention Rates of NHSC Participants and Non-Participants—Primary Care
It is important to note in Figure V.1 that the participants’ retention appears to increase after more than 6 years, while the non-participants’ retention declines at a higher rate than in the previous years. However, these findings should be viewed with caution, because the retention rates for more than 6 years are constructed using only P360 data for 2013, as the timeframe afforded by the Medicare data is only six years (2005-2011).8
In Figure III.2 we present the retention rates in mental health HPSAs. The retention rates of participants are lower in mental health HPSAs than in the case of primary care HPSAs. Also, the decline in retention rates (or the move rate out of HPSAs) is much lower than for primary care providers. For instance, the fraction of participants serving in the same HPSA as during the program is about the same in the first two years since separation (37-38%), declines to 36% and then remains relatively constant at 32-33% thereafter. The retention rate of participants in any mental health HPSA is relatively constant over the years, hovering around 64% and 68%.
Similar to primary care HPSAs, non-participants in mental health HPSAs are much more likely to stay in the same HPSA than participants. Their retention rate declines by 3-4 percentage points each year since the start year, while the retention rate in any HPSA declines at a lower rate, about 2-3 percentage points. It is important to note that the retention rate in any mental health HPSA is very similar across participants and non-participants, especially in the further out years.
Figure III. 2: Retention Rates of NHSC Participants and Non-Participants—
It is important to note that we dropped from the retention analyses in Figures III.1 and III.2 the NHSC participants who left service in 2013, the last year of our timeframe. Of the initial sample of 8,973 participants we identified in the first analytic dataset, we ended up using a number of 6,296 participants, of which 4,995 are primary care providers and 1,301 are mental health providers.
8 The same caveat applies to Figure III.2.