  We compute the two-dimensional correlation functions of the binary black hole
coalescence detections in LIGO-Virgo's first and second observation runs. The
sky distribution of binary black hole coalescence events is tested for
correlations at different angular scales by comparing the observed correlation
function to two reference functions that are obtained from mock datasets of
localization error regions uniformly distributed in the sky. No excess
correlation at any angular scale is found. The power-law slope of the
correlation function is estimated to be $\gamma= 2.24\pm 0.33$ at the
three-$\sigma$ confidence level, a value consistent with the measured
distribution of galaxies.
