diff --git a/documentation/architecture/data-model.md b/documentation/architecture/data-model.md
index 173fc5c04..6e0909c92 100644
--- a/documentation/architecture/data-model.md
+++ b/documentation/architecture/data-model.md
@@ -119,6 +119,7 @@ erDiagram
         string      description
 
         string      version
+        float       score
         date        eta
         date        due_date
         string      status
@@ -767,6 +768,8 @@ Here are the specific fields for requirement assessments:
 - ETA (Estimated Time of Arrival) date 
 - due date. This is for example useful to organize an audit plan.
 
+The compliance assessment score is a read-only field which is calculated when at least one requirement assessment is scored. We calculate the average of scored requriement assessments (ignoring requirement assessments with an undefined score).
+
 Requirement assessments can have attached evidences. An evidence contains a name, a description, an attached file, a url link.
 
 The auditor is free to use the result field (qualitative assessment), the score field (quantitative assessment), or both of them.