The new SIGNOR score combines four features, each taken as evidence of the  support for the functional relevance of the considered causal relationship. Two of these are based on the annotation in SIGNOR.
a.    Number of annotated articles (PMIDs) reporting work that support the interaction
b.    Number of occurrences of the specific relationship in a pathway annotated in SIGNOR
The remaining two features are independent from the SIGNOR annotations and consider the support that is possible to extract from two major curated databases: Reactome and UNIPROT.
c.    Relation occurrence in the “Human Protein Interactions” file that can be downloaded from the Reactome resource.
d.    Number of co-mentions of the two interacting entities in the UNIPROT protein page.
Each feature returns a number n (number of PMIDs, number of co-mentions etc…) that we associate to a “partial score” according to the following formula.

The constant C was empirically fixed to 1.5 for all the features but the first (number of supporting PMIDs) that was set to 2.2 The final combined score was obtained by averaging the four partial scores Below the combined score distribution is depicted as a bar diagram.