The Bullfrog user interface showing the default filter criteria applied to two pairwise comparison files. The default filter criteria include the following: a difference call of Increase (I), Marginal Increase (MI), Decrease (D) or Marginal Decrease (MD), a fold change (ratio) of greater than 1.8, an average difference change (Avg. Diff. Change) of greater than 50 for both files, and an absolute call of present (P) in either the experiment (Exp file) or baseline file (BL file) or both from one or more of the comparisons. The filter checked at the bottom of the screen is 'directional consistency', requiring that the direction or sign of a change is the same in all comparisons.