Alternative Benefit Plan (ABP) regulations have created the ability for states to offer benefit plans tailored to the needs of a particular population, such as the Medicaid expansion population. These regulations require exemption for vulnerable populations, including one new exempt population: the "medically frail." This population includes foster care children and those who meet Social Security disability criteria, but also includes anyone with a serious and complex medical condition or a disabling mental or chronic substance use disorder.

States are seeking a methodology to help them identify the medically frail, one that would be both accurate and administratively efficient. This paper describes a methodology that has been used successfully for identifying a similar population in the Healthy Indiana Plan, a Medicaid expansion program initially authorized in 2008 under 1115 waiver authority.