Felipe Paulino's Game Scores Tell Us Something....

Felipe Paulino has been on a nice roll as the 5th starter in the rotation.  In the last few games, the young hard thrower has been pitching better than a 5th starter.  And, given his stuff, I think he has the potential to be a No. 2 type rotation pitcher. But I'm getting ahead of myself, since that is potential which hasn't been fully realized yet.  We here at TCB like numbers.  And sometimes it's nice to tie everything up in a single number.

That's probably why Bill James invented a "game score" for starting pitchers.  The game score quantifies the quality of a pitcher's performance in one number.   50 or more is the dividing line for a quality start, as defined by this statistic. James' attempt to derive a better measure of "quality start" is one of the reasons for creating game score. The highest nine inning game score in baseball history is Kerry Wood's one hit, no walk, 20 strike out performance against the Astros in 1998 (game score of 105). 

Seven of Paulino's 12 starts have a game score of 50 or more.  Four of Paulino's last six starts have a game score of 60 or more, which is quite good.  Three of Paulino's game scores are over 70, which means an exceptional performance. To put in perspective Paulino's three games scores over 70 (one quarter of his starts), consider this: Tim Lincecum also has three game scores over 70 this year, and Strasburg's start against the Pirates had a game score of 75.  Last year, By comparison, Paulino had nine games with a game score of 50 or more in 23 games.  Last year, Paulino had four games of 60 or more, again out of 23 games.  Perhaps the biggest improvement is in the clunkers.  Last year, Paulino had four games with a score below 20; this year, none.

The pattern of Paulino's game scores is a generally rising trend over the course of the season so far: 43, 40, 44, 39, 50, 72, 23, 59, 51, 75, 73, 63.  The anomaly in that trend is the game in San Francisco, with a game score of 23; and even that was better than his clunker in San Franciso last year, which produced a score of 5.

Based on looking at games scores over decades, Bill James has found that the combination of two numbers, the starter's game score, and the runs scored by the starter's team, are enough to tell you with pretty good reliability whether the team won the game or not.   He has produced tables of win probability expectancy based on combinations of game scores and runs scored.  Using that information, he came up with a quick and dirty formula to determine whether a team should have won the game based on runs scored and game score.  James admits the formula isn't perfect, but in most cases the results are informative.  The formula is [(Runs Scored X Game Score)-50]/286.

The Astros have won four of the games which Paulino started.  (In the last five games, the Astros are 4-1 in Paulino's starts.)  To test James' formula on Paulino's performance, I applied James' formula to Paulino's average game score (52.6) and the team's average runs scored (3.0) in games he started.   This resulted in an average win probability of 38%. Based on 12 games, this produces an expected 4.53 wins. Although Paulino's average game score is equivalent to a quality start, when your team scores, on average, only 3 runs in nine innings, it's difficult to win even half your games. The Astros won pretty close to the win probability predicted by the formula, but possibly the Astros should have won one more game (5).  According to the formula's win expectancy, the Astros had a 73% chance of winning Paulino's first start, mostly because the Astros scored 6 runs, but the Astros lost because the bullpen allowed five runs to score; the Phillies won 9-6.

Comparing Paulino's 1-7 win-loss record to the 4 team wins in his starts indicates that he hasn't been lucky in getting win decisions.  But he has been effective, particularly in recent weeks, in keeping the team in the game so that the Astros can win the game late.