A free throw, a layup and a rebound. If any or all of those plays had gone the Jazz’s way at the end of road games last week, their playoff chances would be more favorable. So would my evaluation of coach Tyrone Corbin. That’s how this stuff works. If Paul Millsap makes a free throw in Milwaukee, Mo Williams converts a layup in Cleveland and anybody in a Jazz uniform rebounds the ball in Chicago, Corbin is judged better. The reality is he’s responsible for those losses. And only if the Jazz make the Western Conference playoffs can Corbin’s first full, 82-game season be considered successful. His team probably overachieved for much of this season, but if Corbin’s work in the first two-thirds of the schedule is undone by the ending, he will have failed. The franchise’s long-range outlook hardly hinges on whether this team qualifies for 2012-13 playoffs as a No. 8 seed. Yet I still say it’s meaningful, and that make-or-miss opportunity will serve as a fair measurement of Corbin. I want to believe in Corbin, I really do. But every time he seems to be proving himself, he regresses. When the Jazz beat Golden State right after the All-Star break, giving him a 75-74 career record, that was monumental. It meant Corbin had gone 70-56 since his 5-18 start after taking over for Jerry Sloan under tough circumstances. His current team stood 31-24, while having absorbed most of Williams’ lengthy absence following thumb surgery.