diff --git a/specification/docs/system-design.md b/specification/docs/system-design.md
index ca479f1..daa1493 100644
--- a/specification/docs/system-design.md
+++ b/specification/docs/system-design.md
@@ -336,7 +336,7 @@ Our prototype demonstrates the simplest possible type of rule that can be applie
  
 ### Validation Pool
 
-The client that each worker operates should be prepared to render a decision on each Executive Validation Pool within its specified duration. For example, if a Work contract submits a VP targeting a particular Work Evidence Post, the Worker client must evaluate this post and determine if it qualifies as valid Work Evidence according to the rules of the DAO.
+The client that each worker operates should be prepared to render a decision on each Executive Validation Pool within its specified duration. For example, if a Work contract submits a VP targeting a particular Work Evidence Post, the Worker client should evaluate this post and determine if it qualifies as valid Work Evidence according to the rules of the DAO.
 
 ### Rollup