Did the use of video replay change this season?

With a year of video replay experience under teams' collective belts, the number of challenges went up this season. In 2014, the umpires donned the headsets 1,275 times, or roughly once every 144 plays. This season, fans had 1,343 chances to run to the fridge. Given the increase in scoring this season, you might expect the increase in replays was a function of more plays, but not so, as one out of every 137 plays was challenged in 2015.

The use of replay rose, despite a decrease in the number of umpire challenges, which were down from 220 last season (17% of all challenges) to 175 (12%). Over the past two years, umpires have most often challenged home runs and home plate collisions, with these two plays making up 74% of the reviews they initiate. The chief reason for the decline in umpire challenges is the reduced number of home plate collision reviews, down from 94 to 31. Despite players and managers voicing their frustration at the seemingly ambiguous rule 6.01(i) at the end of last season, it was far less of an issue in 2015. Players seem to have adjusted to the rule this season, and umpires themselves showed more confidence in their interpretation. Of the 31 home plate collision challenges this season, only two were initiated by umpires. All but one were initiated by umpires in 2014.

Overall, a greater percentage of calls were overturned this season than last. This was driven primarily by the increase in calls overturned after the umpire requested a challenge, although a portion of these came at the managers request after they lost their opportunity to challenge. Manager challenges were slightly less successful this season, dipping one percentage point.

This decreased efficiency may be born of a slightly more aggressive use of the manager's challenge this year. Overall, there were 18% more challenges during the first 6 innings of the game, the period before which a manager with no remaining challenges is able to request one of the crew chief. If you look at the distribution of challenges during the first six innings, managers used them more often in the first and second inning. Rookie skipper Kevin Cash was the most aggressive, challenging 13 plays in the first two innings. No manager challenged more than ten the year before, a mark posted by Kirk Gibson of the Diamondbacks.

In total, 22 managers have worked two seasons under the video replay environment. Both years, Joe Girardi has been the most efficient, getting 73% of calls challenged overturned in 2014 and 79% in 2015. John Gibbons finds himself on the wrong end of this leaderboard, having been among the worst each of the last two seasons.

Most improved was Bryan Price, who shot up from 41% to 66% efficiency on calls challenged. Not that anyone needs another reason to pile on Matt Williams, but the percentage of his challenges that were overturned plummeted from 65% to 43%. This probably won't help him on the job hunt, though it will likely be among the least of his prospective future employer's concerns with his managerial moves this year. If it does come up in interviews, he can cite the low correlation of percentage calls overturned across the two seasons for the managers in this group (r=0.30).

The umpiring crew in New York was also slightly less efficient with their handling of calls challenged on the field. Reviews took slightly longer this year, averaging one minute 51 seconds, up five seconds from the season before. This was the result of a handful of particularly long replay reviews, as the median time for 2015 was up just one second (1:39) from the year before.

Overall, there was little change in the use of video replay this season compared to last. This should come as little surprise, given that umpires routinely give teams the chance to review the play themselves before signalling to the manager whether a challenge should be made. Maybe the biggest surprise is that, despite this courtesy, teams still can't get more than half of the calls they challenge overturned.

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Matt Jackson is a featured writer for Beyond the Box Score and a staff writer for Royals Review. You can follow him on Twitter at @jacksontaigu.