Repeatability (r)

• Repeatability (R) is a measure of the strength of the relationship between repeated records (repeated phenotypic values) for a trait in a population.
• Repeatability can be estimated for any trait in which individuals commonly have more than one performance record.
• The repeatability of the production of male mating signals gives information both about whether males differ sufficiently for selection to act and whether the differences could be appreciably heritable.
• Measures of the repeatability of female mating preferences will provide data that can describe the preference functions used in mathematical models of the evolution of sexually selected traits, as well as putting an upper bound on the heritability of preferences.

Repeatability is the correlation between repeated records for a trait in a population.

R = rP1P2

Repeatability can also be thought of as a ratio of variances. It is the ratio of the variance of producing ability to the variance of phenotypic value

R = σ2PA/ σ2P

The range of repeatability is from 0 to 1, or from 0 to 100%