The Steelers were trailing the Dolphins by 2 points with 2:28 to play. After a very controversial replay, which I won't get into here, the Steelers faced 4th and goal from inside the 1. They elected to kick a FG, and hung on to win 23-22. But should they have gone for the TD?
FGs from that range are virtually automatic. But with that much time left, a FG gives the Dolphins plenty of time to get into FG range in response. With a FG and a 1 point lead, PIT would have a 0.59 WP.
Going for it from the one on the goal line would typically be successful 68% of the time. A TD and a 6 point lead would make MIA's task that much tougher, giving PIT a 0.74 WP. A failed attempt would give MIA the ball inside their own 1, worth about 0.19 WP for PIT. I say 'about' because there are few examples of teams backed up on their own goal lines with a 1-point lead.
In total, going for the TD is worth:
(0.68 * 0.74) + (0.32 * 0.19) = 0.56 WP
In this case, kicking the FG is the percentage play, but it's very close. The break-even probability of success is 72%, not far off from the baseline of 68%.