3 The ability to control health-care costs, while still providing high-quality care to those who need it, will be critical for bringing the federal budget onto a sustainable path. The retirement of the baby-boom generation will also strain Social Security, as the number of workers paying taxes into the system rises more slowly than the number of people receiving benefits.
ii)  Another part of the process, though, is inherently subjective and remains fundamental in deciding which models are really relevant and how results should be interpreted.