To the Editor.
—In the excellent article by Mr Showstack and colleagues,1 the authors argue that, from a societal point of view, managed care systems should adopt a population perspective: these systems depend on publicly financed assets (eg, Medicare and Medicaid managed care) and may draw resources away from the traditional systems mandated to provide for the uninsured. The authors also suggest that investment in the health of society is a prudent business strategy to improve community relations and to obviate legislative mandates.We suggest 2 additional reasons why a managed care system might, for entirely self-interested reasons, reach beyond its enrollees and focus on the health of the population at large. First, the enrollment populations for managed care plans have been noted to be increasingly unstable. When patients change plans frequently, the concept of an enrolled population loses much of its meaning and the health of nonenrollees becomes highly