Causality

Gerontologists are often skeptical of age as a presumed cause of the aging process. Although age is an indispensable marker of life experiences, it is a rather crude indicator of the many factors that actually shape the aging experience, including senescence. To address the multiple meanings associated with age, some gerontologists have advanced concepts such as biological age or functional age. These are useful concepts, isolating one domain or facet of aging, but even these concepts must be applied with a skepticism for age effects. Gullible gerontology ensues when well-meaning persons accept age as an explanatory variable and disregard or minimize other factors or processes that are associated with age differences. Gerontologists prioritize longitudinal research designs and urge caution when one attempts to generalize from age differences. Concepts such as terminal drop and the age-period-cohort are used to illustrate this axiom.