Lincoln index A simple estimate of animal population density, based on data obtained by mark-recapture techniques. It is written as: P = an/r, where P is the estimate of population, a is the number of marked individuals released, n is the number in the subsequent sample of captured individuals, and r is the number of marked individuals recaptured. It was devised in 1930 by the American ornithologist Frederick C. Lincoln.

Lincoln index A simple estimate of animal population density, based on data obtained by mark-recapture techniques.