A word in daily use, and two kinds of definition

People use the word for an older person constantly — in ordinary talk, in policy and administration, and in study — and a clearer line is needed before gerontology, or the welfare of older people, can be discussed with care. Abstract definitions and operational ones are held apart.

An abstract definition, in line with what Breen argued, is that biological, psychological, or social aging must be part of the idea: a person in a period of physiological or biological decline; a person whose mental function and personality are changing; and a person whose social status and role have been completely lost. The Second International Gerontological Congress, in 1951, defined the older person as someone whose organised capacity to adapt to a changing environment is gradually fading; whose own integrative capacity is gradually fading; or who is in a period when organs, tissues, and functions are in decline. Taken together, the older person is someone in whom physiological and bodily decline, and mental and psychological change, have greatly weakened the functions of self-maintenance and of social role.

Operational definitions then split four ways: by a person’s own sense of age, by the loss of a social role, by chronological age, and by functional age. The comparison here is between the last two.

What a body can still do, and what the calendar says

Functional age has been developed especially in industrial gerontology. Under that idea, a person is treated as older when they cannot adequately do a particular physical, psychological, or social task, even if other capacities remain. The strength of the definition is that it takes seriously how differently people, and the parts of one life, age. The weakness is practical: the judgement takes a long time, and the criteria are still not clear or objective, so convenience is weak. The writer holds that valid professional indicators of bodily, psychological, and mental development and decline would have to be in place first, and that building such indicators is itself very hard, so a purely functional line is, in practice, almost impossible. Under that rule a young person could be classed as older; the writer thinks another kind of measure would be more fitting in that case.

Chronological age counts years on the calendar, and generally treats a person of 65 or more as older. It is easy to observe, convenient for law and administration, and the most common definition in use. Its weakness is that everyone over 65 is treated as one group, without regard to personal difference, including the difference in what a person can still do; stereotypes and prejudice can follow. The line of 65 itself is treated as arbitrary. Most industrial societies follow a tradition set in 1889, when Germany’s old-age pension law, described here as the first of its kind, set eligibility at 65.

Because a single group from 65 to 80 or 90 hides personal and social difference, Neugarten argued that 55 to 74 as the young-old, and 75 and over as the old-old, was a better fit, and Brody argued for 60 to 64, 65 to 74, and 75 and over. From the 1990s, as longer average lives came more clearly into view, a four-band split has been more often used: 65 to 69 as the young-old, 70 to 74 as the middle-old, 75 to 84 as the old-old, and 85 and over as the oldest-old. The ages at which those bands are drawn, the writer adds, should move with a society’s economic, social, cultural, and demographic character.

Yamada’s gap, and a 2016 remark about Korea

A blanket chronological line, the comparison says, ignores personal difference, especially the difference in what a person can still do. The Japanese scholar Yamada, combining various physical tests and intelligence tests, set out the gap clearly: at a chronological age of 25, the difference from functional age was about four years, a functional span of roughly 23 to 27; as chronological age rose, the gap grew, and at 75 it was about 18 years, a functional span of 66 to 84. A person may therefore be younger or older in function than the calendar suggests, and the error is large. Those figures are left with Yamada as they are given. If a convenient way of measuring function were well developed, the writer thinks, a functional line could be fairer, and could recognise difference.

Set side by side, a functional line can honour difference but has been too vague to be effective in practice; a chronological line is effective and clear, but ignores difference. In 2016, the writer notes, average life in Korea for women and men had already passed 80, and a new custom of celebrating 70 rather than 60 as the arrival of later life was appearing. On that basis the writer proposed bands of 60 to 69, 70 to 74, 75 to 84, and 85 and over, and held that a compromise between function and the calendar would be the most effective standard. The remark about average life is left with 2016.

Why the calendar and the body both matter

A single birthday is easy to administer, and a body that can still do the work is a fairer picture of a life. The useful line, in this telling, sits somewhere between the two. The same Korean report, at fuller length, is on CampusDown.

Sources

1. Essay on the concept of the older person, comparing functional age and chronological age (Korean source page).
2. The Second International Gerontological Congress, 1951, as cited for an abstract definition. Breen, as cited on the need to include biological, psychological, or social aging.
3. Neugarten, on the young-old (55–74) and the old-old (75 and over). Brody, on bands of 60–64, 65–74, and 75 and over. The Japanese scholar Yamada, on gaps of about four years at chronological age 25 and about 18 years at 75. Germany’s old-age pension law of 1889, setting eligibility at 65.
4. Park Cha-sang, Korean Elderly Welfare, Hakjisa, 2007. Kwon Jung-don, Elderly Welfare, Hakjisa, 2013. Choi Sung-jae, Elderly Welfare in an Aging Society, Seoul National University Press, 2010. The writer’s 2016 remark that average life in Korea had passed 80 is left with that year.

Last updated: 14 November 2026