  In this letter we show that in a Gaussian random field the correlation
length, the typical size of correlated structures, does not change with
biasing. We interpret the amplification of the correlation functions of subsets
identified by different thresholds being due to the increasing sparseness of
peaks over threshold. This clarifies an long-standing misconception in the
literature. We also argue that this effect does not explain the observed
increase of the amplitude of the correlation function xi(r) when galaxies of
brighter luminosity or galaxy clusters of increasing richness are considered.

Astrophysics;Statistical Mechanics