What is the test for reviewing an arbitrator’s decision?

I must first determine the standard on which the arbitrator’s decision should be reviewed. The four factors outlined in Pushpanathan v. Canada, 1998 CanLII 778 (SCC), [1998] 1 S.C.R. 982 must be considered: 1. the presence or absence of a privative clause; 2. the expertise of the tribunal; 3. the purpose of the governing legislation as a whole and the provisions creating the tribunal and its role; and 4. the nature of the problem, i.e. is it a question of fact, mixed fact and law, or law?