S. Vandongen, HOW REPEATABLE IS THE ESTIMATION OF DEVELOPMENTAL STABILITY BY FLUCTUATING ASYMMETRY, Proceedings - Royal Society. Biological Sciences, 265(1404), 1998, pp. 1423-1427
The estimation of individual fluctuating asymmetry (FA) is subject to
large sampling variabilities. Heritability estimates, as well as corre
lations between developmental stability and any other individual chara
cter and/or between-trait correlations, are consequently biased downwa
rd if FA is used as an estimate of an individual's ability to buffer i
ts development against developmental noise. The estimation of the hypo
thetical repeatability, defined as the ratio of the between-individual
component of variation in the unsigned FA divided by the total varian
ce, allows correction for these biases such that patterns observed for
FA can be translated to make inferences about the presumed underlying
developmental stability. In this paper I show that previous estimates
of this repeatability are incorrect. I provide a new method and show
by means of simulations that the hypothetical repeatability is in most
cases even lower than previously thought. This has important conseque
nces for the analysis of FA with respect to statistical power and the
interpretation of patterns in FA.