Risk vulnerability and enrollment in a prepaid group practice.
An hypothesis that specifies conditions under which risk vulnerability factors are associated with enrollment in prepaid practices is presented and tested.  We assert that such factors as illness histories and previous use of medical services are linearly and positively associated with enrollment when the prepaid option offers significantly lower marginal out-of-pocket costs.  The hypothesis is supported by observations from a prostpective study of a lowincome population.
D001741:Black or African American; D001294:Attitude to Health; D004608:Eligibility Determination; D005191:Family Characteristics; D006123:Group Practice; D007182:Income; D007357:Insurance, Physician Services; D008396:Maryland; D008484:Medicaid; D011336:Probability; D012306:Risk