1) Clarity 2) Logic 3) Rigour 4) Validity 1) Convincing quality 2) Logical appeal 3) Persuasive relevance 4) Persuasiveness 5) Relevance 6) Relevancy 
• (n.) The quality of being cogent; power of compelling conviction; conclusiveness; force.
(from the article `logic`) ...intended to support the conclusion only to a lesser degree, the argument is called inductive. A logically correct deductive argument is termed ...
Co'gen·cy noun [ See Cogent .] The quality of being cogent; power of compelling conviction; conclusiveness; force. « An antecedent argument of extreme cogency . J. H. Newman. » 
[n] - persuasive relevance 2. [n] - the quality of being logically valid
cogency The quality or state of being convincing or persuasive.
noun the quality of being logically valid
the quality or state of being convincing or persuasive: The cogency of the argument was irrefutable.