Funnel plots of VarTD from four published data sets. Funnel plots of Variation in Taxonomic Distinctness (VarTD) from (a) bivalves , (b) carnivores , (c) coleoids , and (d) termites  data sets are shown. Results are from 100 random replicates. Thick lines are the upper 95% confidence limit and the lowest values found across all replicates of each dimension; the thin line is the mean across all replicates; experimental samples are shown by black dots. The bias towards lower values for small sample is detectable in mean.
Plazzi et al. BMC Bioinformatics 2010 11:209 doi:10.1186/1471-2105-11-209