Effect is a type of Validity. Validity is related to Reliability. Reliability is derived from Ability. 
Researcher is a type of Worker. Worker is related to Peasant. Peasant is related to Class. 
Effect --IsA--> Validity <--RelatedTo--> Reliability --DerivedFrom--> Ability 
Researcher --IsA--> Worker <--RelatedTo--> Peasant <--RelatedTo--> Class 