Clustering in the MUSIC and FIDEL catalogs as a function of scale. The ratio of the variance of the number of sources to the mean number of sources within a circle is plotted against the diameter of the circle for both the MUSIC and FIDEL catalogs. For a Poisson-distributed catalog, this ratio would be unity at all scales. Each point in the graph is the variance (divided by the mean) of the number of entries that fall within 500 randomly placed circles of a given size within the respective survey area. The broken vertical lines indicate the BLAST FHWMs. Notice that the FIDEL catalog retains a Poisson distribution to larger scales than the BLAST beams, while the much deeper and heterogeneous MUSIC catalog shows excess variance arising from the clustering of galaxies at all angular scales.