Use Lincoln Petersen Estimator when you need to estimate population size from two capture sessions with the Lincoln Petersen index. Enter First capture count, Recaptured count, and Second capture count using the definitions and units below so the result can be reproduced.

First capture count

An integer count or setting greater than or equal to 1, expressed in individuals.

Recaptured count

An integer count or setting, expressed in individuals.

Second capture count

An integer count or setting greater than or equal to 1, expressed in individuals.

The published tool contract uses this rule: Estimate population size from two capture sessions with the Lincoln Petersen index.

Population estimate

The calculated population estimate in individuals.

The output is an estimate tied to the stated model and coefficients; it is not a direct measurement and should retain that label when reported.

Retain the original First capture count, Recaptured count, and Second capture count values and their units alongside the result. Schnabel Estimate is useful when you instead need to estimate population size from a documented two sample Schnabel census. Chao1 Estimator provides another view by helping you estimate total species richness from singletons and doubletons in a single sample using the Chao1 estimator.

• Schnabel Estimate

  Estimate population size from a documented two sample Schnabel census.

• Chao1 Estimator

  Estimate total species richness from singletons and doubletons in a single sample using the Chao1 estimator.

• Chao2 Estimator

  Estimate total species richness from incidence data across samples using the Chao2 estimator.