All I know of is that his rule for contenders is "40 wins before 20 losses". But there are three ways to read that.

1. You are a contender if you win 40 games before losing 20. This means following the rule is sufficient to be a contender, but not necessary - other teams can be contenders.

2. You are a contender only if you win 40 games before losing 20. This means it's a necessary but not sufficient condition - you must follow it to be a contender, but even if you do, it could be a fluke that means you're not a contender.

3. You are a contender if and only if you win 40 games before losing 20. This means it's both necessary and sufficient - the set of contenders is equal to the set of teams who win 40 games before losing 20.