Definition:Capture-Recapture Sampling/Warning

Capture-Recapture Sampling: Warning

Capture-recapture sampling tends to overestimate the population size, especially for small $m$.

The validity of $N^*$ depends strongly upon the assumption that both the population size and the probability of capture remain constant between samples.

The former assumption ignores births, deaths and migration between sampling, and the latter does not hold if the animals decide they like being captured (perhaps because they get fed).

Alternatively, if an animal is frightened by capture, this may reduce the probability of recapture.

More sophisticated estimators take some of this into account.

Sources

• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): capture-recapture sampling
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): capture-recapture sampling