survivorship

Survivorship is a term used across disciplines to describe the fate of individuals beyond a specified point in time, and, more broadly, the study of survival patterns within a population. In demography and ecology, survivorship refers to the probability that a member of a cohort will survive to a given age or life stage. The concept is commonly illustrated with survivorship curves, which plot the proportion of a cohort still alive at each age. There are several typical patterns: Type I curves show high survival in early and middle life with steep decline in later years (as seen in humans and many large mammals); Type II curves reflect a roughly constant mortality rate across ages; Type III curves indicate high juvenile mortality with many individuals failing to reach adulthood (as seen in many fishes and invertebrates). Data are typically drawn from life tables, cohort studies, or survival analyses such as the Kaplan-Meier method.

In medicine, survivorship refers to the phase of care after a diagnosis of cancer or other serious disease, focusing on physical recovery, psychosocial well-being, late treatment effects, and ongoing monitoring. It also appears as a statistical concept known as survivorship bias, where observed outcomes may be skewed by the preferential survival of certain cases.

Survivorship as a field of study informs conservation, public health, and policy by describing how populations endure, decline, or recover over time.