Fold enrichment provides a measure of the specific signaling activity for each identified kinase. This value is calculated as the ratio of significant targets for a specific kinase (relative to the total number of significant sites) divided by the proportion of that kinase’s total known targets within the entire background dataset. Biologically, a high Fold Enrichment value suggests that the kinase’s activity is being strongly and specifically modulated in your experimental condition, allowing you to statistically infer upstream signaling drivers directly from your phosphoproteomic data.