Here is a great excerpt from, “Long Term Care: Definition, Demand, Cost, and Financing” by Nelda McCall

“Estimating demand for long term care needs is complicated because it involves consideration of the prevalence of medical diagnoses and of limitations in functional abilities. Individuals need long term care when trauma or a chronic condition limits their ability to perform independently those personal activities necessary to daily living. One common way of measuring the level of disability is by assessing an individual’s ability to perform specifically defined ADLs and instrumental activities of daily living (IADLs). ADL measures include such tasks as eating, dressing, bathing, walking, transferring, and using the toilet. IADLs relate to the ability to perform household chores and to participate in social activity, measuring such tasks as preparing meals, doing light housework, keeping track of money or bills, using the telephone, and going outside the house.

The estimate of individuals with functional limitations in a population has differed across data sources as individual analysts use different definitions of limitation, different specific ADL and IADL measures, and different thresholds for the number of ADL and IADL impairments to define a functional limitation. Komisar, Lambrew, and Feder (1996) attempted to define the type of personal assistance that would be characterized as long term care.2 Their estimate of the number of individuals with functional limitations in 1995 was 10.6 million, with 4.8 million under 65 years of age and 5.8 million over 65 years of age (Table 1.1). For the under-65 group, the prevalence of disabilities was estimated to be 2.1 percent; 4.6 million people were community residents with functional limitations, and 229,000 were nursing home residents. For the 65-and-over population, the prevalence of disabilities was estimated to be 17 percent; 4.1 million were community residents with functional limitations and 1.7 million were nursing home residents. Other estimates of the percent of those 65 years and older with disabilities were between 16 and 21 percent (Siegel 1996; McNeil 1997; Manton, Corder, and Stallard 1997).

Disability is dramatically related to age as seen by the more than eightfold difference in the prevalence of disability between those under 65 and those 65 and older (Komisar, Lambrew, and Feder 1996). Given this relationship, the projected acceleration of aging of the U. S. population is of special concern.

The number of elderly and their percentage of the total population will grow dramatically as a result of the aging of the baby boomers, those people born between 1946 and 1964. The U. S. Census Bureau estimates that in 1998 34.3 million persons in the United States, or 12.7 percent of the total population, were over the age of 65 (U. S. Bureau of the Census 1996). Because of the relatively small number of children born during the Depression, the growth of the older population was relatively slow during the 1990s. However, between 2010 and 2030, when the baby boomers join the ranks of the elderly, the older population is expected to double.”