The “diffusion” diffusion” of physicians The Diffusion of Physicians Thomas C. Ricketts, Ph.D. Randy Randolph, M.R.P. University of North Carolina at Chapel Hill z Economists argue that there is marketmarketresponsive diffusion from urban (more dense) to rural (less dense) places. (Newhouse, Newhouse, Rosenthal, Zaslavsky) Zaslavsky) z The number of rural (and Urban) physicians has increased overall. z There is a mixed pattern of gains and losses. Change in Primary Care Physicians to Population Ratio, 1995-2001 Question z What are the factors that predict migration of physicians? VEconomic VPersonal VEcological Alaska and Hawaii Not to Scale *See Note Change in PC Physician to Population Ratio (# of Counties) 1.67 to 17.1 0.79 to 1.66 0.01 to 0.78 No Change -0.01 to -0.41 -0.42 to -1.24 -1.25 to -15.6 (713) (713) (698) (200) (301) (258) (258) *Alaska's state total is 2.47. County data were not available. Sources: AMA Masterfile as reported in : HRSA, BHPr. Area Resource File, 2002. Produced By: North Carolina Rural Health Research and Policy Analysis Center, Cecil G. Sheps Center for Health Services Research, University of North Carolina at Chapel Hill. How we did this? z We linked the AMA Masterfiles from 1981, 1986, 1991, 1996, 2001, (2003) by individual physician records z Practice locations were linked to ARF data for counties VIncome, employment, race, education VPhysician supply, hospitals z We looked at physicians who moved from one county to another (MOVERS) between 1981 and 1991 and 1991 and 2001 Specific Questions z Did doctors who moved move to places with fewer docs (less demand)? z Who were the MOVERS and who were stayers? stayers? z Were there other factors that influenced where MOVERS went? 1 Movement by Physician Density Deciles 19911991-2001 Movers/Stayers, Movers/Stayers, 19811981-2001 Low TO 1981-1991 1991-2001 Total active both years 297,466 Moved Stayed 95,923 (32%) 201,541 To different state 58,709 (61%) Female 15,632 (43%) New to practice 19,418 (72%) Primary care 27,064 (26%) Total female 36,297 Total new to pract. 25,596 Total primary care 92,145 Total active both years 424,154 Moved Stayed 152,829 (36%) 271,325 To different state 93,989 (61%) Female Total female 38,535 (43%) 88,239 New to practice Total new to pract. 61,240 (76%) 85,512 Primary care Total primary care 41,624 (27%) 152,829 Long Term and Regional Flows z 83,383 Of 254,226 physicians (1981(1981-2003) were in primary care in both years. 59.3% remained in or returned to the same county 27.4 moved within region and type of county 13.2% moved to another ruralrural-urban type of county or different region VFlow from the Northeast and the Midwest to South and West VNet flow from central metro counties (-2,512) to small metro and adjacent counties, +1,837 VSmall net gain to nonmetro, nonadjacent, +675 Regression results Odds Ratios (Change of Sign, Significant Both Years) Variables 1981-1991 FROM TO 1991-2001 FROM TO Female 1.189 1.359 1.074 Age 0.903 0.900 0.907 0.901 Prim Care 0.974 0.750 0.990 0.733 Population 1.000 1.000 1.000 1.000 Ratio 1.053 0.955 1.010 0.991 Highsch % 1.000 0.998 0.998 0.999 Unempl 1.005 0.998 1.024 0.985 Nonwhite 1.011 0.996 1.013 0.996 Income 0.956 1.014 0.986 1.005 Hosp 0.984 1.006 0.964 0.993 1.187 1 2 3 4 5 6 7 8 9 10 Total 1 2,809 1,946 1,432 923 1,101 1,142 1,055 1,162 919 517 13,007 2 2,145 1,627 1,582 1,181 1,048 1,071 795 1,026 797 654 11,928 3 1,979 1,646 1,373 844 929 1,180 943 1,039 1,257 629 11,822 4 1,874 1,894 2,082 1,553 1,353 1,391 1,221 1,284 1,101 1,904 15,661 FROM 5 1,202 1,601 1,352 1,337 1,743 929 897 767 755 700 11,288 1991 6 2,741 2,305 2,218 1,632 1,926 2,055 1,696 2,746 1,816 1,852 20,993 7 1,252 1,178 1,358 1,026 903 1,037 1,013 931 1,092 989 10,786 8 2,273 2,149 1,897 1,668 1,566 1,773 1,467 1,864 1,627 1,099 17,391 To Higher Ratio Class Same Ratio Class To Lower Ratio Class 9 1,414 1,688 1,775 1,512 1,902 1,976 1,353 2,326 2,401 2,576 18,932 High 10 1,386 1,829 2,237 1,714 1,616 2,165 2,150 2,343 2,555 3,071 21,076 total 19,076 17,865 17,309 13,394 14,092 14,725 12,597 15,496 14,329 14,001 152,829 35.2% 12.8% 52.0% Multivariate analysis z Two models predicting MOVE, one for each 1010-year period z County variables for Departure county relate to initial year: 198119811991 z County variables for Destination county relate to later year, 19911991-2001 Conclusions z Physician supply is dynamic, 33% in 5 yr period z Physicians go to places with fewer other MDs but higher per capita income, fewer nonnon-whites, and lower unemployment z Policies should recognize the dynamic nature of the supply when considering: VEvaluation of programs (e.g.: retention rates in context of normal flows) VPlacement (prepare physicians for inevitable geographic change) VThe economic argument that diffusion meets needs is confirmed but conditioned 2