Saturday, 24 October 2015

Palmer on DiPS

Pete Palmer was interviewed in April of this year, and was asked about Voros McCracken's Defence-Independent Pitching Statistics. Palmer is arguably the most important sabermetrician OF ALL TIME. Certainly his only rival is going to be Bill James, so reading Palmer's comments on DiPS theory, which James himself regarded as important, makes an interesting comparison and contrast.

James referred to McCracken's work in the New Bill James Historical Baseball Abstract (p 885):

3. This knowledge is significant, very useful. 4. I feel stupid for not having realised this thirty years ago.
Palmer, however, has a very different take on the matter.
I didn’t have a lot of faith in [DiPS]....[McCracken] said there wasn’t a great amount of correlation from season to season. But as I said, the variations due to chance and everything in sports, baseball in particular, is a lot higher than people think. Your average could drop 60 points from one year to the next, and it’s not really statistically significant because 500 at-bats isn’t that many at-bats to verify what your current batting average should be.
Whether this opinion is rooted in statistical analysis or not, it does conform somewhat with the analysis provided in "Solving DiPS", a compilation of an on-line discussion which you can find a copy of here. One key solution in "Solving DiPS" is that, given 700 Balls in Play, some 44 per cent of the outcomes are a consequence of random variance, the single largest factor. (Pitchers were assigned 28 per cent, fielding 17 per cent. Hold that thought for a moment.)

I have seen it suggested that Palmer does not understand DiPS, which has become a tool for projecting a pitcher's future. But from the perspective of evaluating a pitcher's season, Palmer's lack of "faith" makes more sense. BABIP's variance is irrelevant, because it is in the nature of the game. What is important is to convert extra-base hits into singles, and singles into outs.

When you don’t look at walks and strikeouts and home runs, you’re actually minimizing a difference between a good pitcher and a bad pitcher. And therefore, the gap in that category is going to be artificially low because some of the factors that would make it higher are not counted.
In other words, we shouldn't be surprised that pitchers appear to have limited or no control over the outcomes of balls in play. That has never been where the difference has been visible in the small sample size of a single season.

Finally, to return to those percentages from "Solving DiPS", what might be surprising from the traditional reception of DiPS is that pitchers have more control over the outcome than fielders. So, again, perhaps we should be a bit more sceptical, like Pete Palmer, of those making grandiose claims for DiPS. Insofar as anything has control over the outcome of the batted ball, it is the pitcher. Random variance in its nature is uncontrolled.

Thursday, 22 October 2015

Oh, the Humanities

As I tweeted a week or so ago, this was a good season for the part of me that is a Tigers' fan to miss. I have been dealing with a return of my wife's cancer (the outlook is not great but, as the last lines of the original theatrical release of Blade Runner go, "I didn't know how long we had together... Who does?"), in addition to moving house (and changing countries). However, I accumulated a few bookmarks and other ideas to work through, especially now we can only watch other teams in the post-season.

While I was busy, a very important blog post was made back in May. Phil Birnbaum, who is nothing if not insightful in writing about sabermetrics, announced that dWAR, a measure of fielding value, seemed to him to have a significant problem. Birnbaum proposed that dWAR inherently overvalued fielding. Birnbaum's argument is rooted in mathematical accuracy, so I don't feel confident trying to explain it. If you haven't read the post already, you should go to his blog to read how he explains it.

However, his explanation boils down to three key points, if we focus on the effects:

a) the runs allocated to the fielders under dWAR are too high, by an order of around fifty percent. (So a team dWAR of -40 is actually more like -20

b) The cause of this is that when one assumes "certain balls in play are the same" (as one has to do with older baseball statistics) then the math sends all the credit to the fielders.


"Observations are a combination of talent and luck. If you want to divide the observed balls in play into observed pitching and observed fielding, you're also going to have to divide the luck properly."
Here, I think, we run into the problem of "All things being equal", or the distinction that the philosopher of history R.G. Collingwood made between meteorology and chemistry. It is an essential fact of human life that all things are NOT equal. People working in meteorology can collect observations of events, but cannot reproduce them at will, unlike people working in chemistry. By contrast, the historian can observe events, but they cannot create political or social crises at will, nor send qualified observers back into the past in order to collect the information needed to understand those events in the way scientists might send an expedition to view an eclipse or collect specimens. In scoring a baseball game, at best a sabermetrician can be a weatherman.

One can take issue with the statement "the assassination of Archduke Franz Ferdinand of Austria on 28 June 1914 triggered the First World War" as one of causality, but without doubt the shooting set off a diplomatic crisis that led to the war. More importantly, luck played a crucial role in the event because the Archduke's car came to a complete halt very close to where the "Yugoslav nationalist" Gavrilo Princip, had stationed himself. An earlier attempt to kill the Archduke in a moving car had failed. We have no idea whether Princip could have been successful if his targets had been in a moving car. So, what percentage of responsibility to the war do we assign to Princip, to the driver, to the governor of Bosnia at whose orders the driver stopped, to the Serbian officers who conspired to arm Princip, to the Archduke or to the general diplomatic situation? And any formula that did allocate "responsibility shares" to these people would be essentially an act of faith.

Birnbaum went on to add some further details to his understanding in a threat on the blog of Tom Tango, the tremendously influential pseudonymous saberist. In the comments section of Tango's thread on the post by Birnbaum, Birnbaum suggested in one reply that it was just not possible for a system like Defensive Runs Saved or Ultimate Zone Rating to make distinctions about balls in play that could tell us something about the skill of the fielder.But before that he stated that he wanted to assign the luck to the pitcher. However, reading the comments there is to venture into a world where something like the Responsibility Shares is thought to be possible. Possibly, with enough computing power, such things can be made for evaluating baseball players. But I can't help but think the effect will be small.

To reduce Birnbaum's position down, what he thinks is that about half of the dWAR effects at the team level need to be transferred from the fielder to the pitcher. Another way to think about it is that he wants a cap on the amount of Runs Allowed value distributed to the fielders. But this would also have effects on how we value players. A quick-and-dirty method would be to halve the UZR assigned to any player when calculating their WAR, although I suspect Birnbaum would object on the grounds that something true at the team level may not be true at the level of the individual player.

Monday, 20 April 2015

2015 Tigers' Series #4: potentes Cespedes

Ave Yoenis! What do the two Tiger victories in the weekend series against the Chicago White Sox have in common? Home runs by Yoenis Cespedes. They also have in common excellent pitching, from David Price and Shane Greene. Meanwhile, Saturday's blow-out loss featured very poor pitching. Even the bullpen gave up three runs in the first two innings after Anibal Sanchez was knocked out of the game. Once again we see Brad Ausmus a bit reluctant to go the pen, although he may have been trying to eke out enough innings from Sanchez to keep some relievers in reserve for the series with the New York Yankees.

Cespedes has now improved his Steamer projection to a wRC+ of 122, up three runs on what was forecast before the season. However, more importantly, shortstop Jose Iglesias has raised his wRC+ projection to 96, from 81. Almost all of the projections for Tigers' hitters are up, but Iglesias' improvement is the most dramatic. Of course, the season is long, and much can go wrong between now and October. Iglesias fine start is based on an outrageously unsustainable BABIP of .459. (It is worth noting, however, that JD Martinez' BABIP is an equally implausible .212.) However, one can't take away those ten wins from the Tigers. The Tigers went 10-2 where pre-season projections implied a 7-5 or 6-6 record. Tigers' fans should be happy, and send positive feelings toward a team that is doing them proud.

Numbers indicate what percent of a win a player added over the series with his bat, based on Run Expectancy and Leverage of plate appearances.

Player               Win Value Added
Yoenis  Cespedes       .987
Jose  Iglesias         .407
Anthony  Gose          .183
Nick  Castellanos      .163
James  McCann          .021
Andrew  Romine         .000
Hernan  Perez         -.005
Miguel  Cabrera       -.039
Rajai  Davis          -.090
Victor  Martinez      -.095
Alex  Avila           -.127
J.D.  Martinez        -.323
Ian  Kinsler          -.523

Friday, 17 April 2015

Octo Lauri

EIGHT AND ONE! Is this egg all over the faces of Tigers' sceptics like Baseball Prospectus' Sam Miller, who has mentioned in a couple of podcasts that he thinks the Tigers will escape the AL Central cellar by one spot? Or should we be more cautious and remember the old sage Aristotle's comment that "one swallow does not make a summer"? Let me line up a few mid-April thoughts as we still remind ourselves that it is a long season, and much can go right during it, as well as going wrong.

The BIG MAN: The Tigers are going to stand or fall by the production of Miguel Cabrera. Last season he looked weak at times, like Antaeus being lifted up by Hercules, but only for a moment. I have only been able to follow the games by GameDay Audio, but the sense I get is that he is still missing a bit of the power that made him the linch-pin of previous Tigers' teams. What we have at the moment is a Cabrera more akin to Victor Martinez, who is hitting hard line-drives for singles and doubles. If he can still hit for a high average with a goodly amount of gap power, he will remain the offensive force that the Tigers need batting in the third spot. I was optimistic from the first plate appearances in spring training that Cabrera would prove all those neo-sabermetric Cassandras wrong, and I remain so.

The Rotation: Like classic Dave Dombrowski teams, the Tigers are going to win with starting pitching. This was his strategy with the Florida Marlins in 1997, and it was what he was rebuilding in 2001, when he came north. Starting with the trade of Doug Fister in November 2013, Mr Dombrowski began rebuilding the rotation on the fly. It seemed to me the trade for David Price was not a short-term patch, but has long-term intent, as Mr Dombrowski is looking to sign him to the kind of contract Max Scherzer turned down. More importantly, after two starts it looks as if Shane Greene is the real thing. However, I am slightly concerned by our Latin AS-Team of Anibal Sanchez and Alfredo Simon. Sanchez' disastrous seventh inning on 13 April reminded me that it is one of his characteristics, to lose it quite rapidly. I would like to see Simon pitch a few more DH games before I regard his starts with a degree of confidence. The big question, though, is whether a Justin Verlander start will be any better than a Kyle Lobstein one. Lobstein did well enough for the Tigers to win the game, but those are games that must be won by the bat, an uncertain hope still, even with a return to fearsome form by Miguel Cabrera.

Cheetahs Prosper: Brad Ausmus' decision-making in these early games suggest that he plans to make full use of his speedier chaps this season. We have seen some benefit with Anthony Gose in centre-field, but the running game is a chancer's hope. So far, the Tigers are on a hot streak, but Gose was caught stealing in the first inning on 10 April, an incident followed by two singles that might have given the Tigers an early lead in a game they never looked like losing — but we didn't know that at the time. As long as Ausmus' decision to run is rewarded with success, I'm happy to see the Go-Go Tigers. But I reserve the right to say indiscriminate basepath larceny will only lead us to remember that crime does not pay.

Oh What a Relief It Isn't: The Tigers have been fortunate that their bats have carried them through two of the three series they have played so far. In Pittsburgh, playing by the National League's primitive arrangements of letting the pitcher bat (my goodness, but Dan Dickerson went on and on about that to the point of making me reconsider my On the Road to Damascus conversion to the Designated Hitter a couple of years ago), Manager Ausmus used a grand total of four relief pitchers in three games, none of which was settled by more than two runs. Meanwhile, Manager Hurdle used EIGHT. Ausmus' reluctance to go to the bullpen in high-leverage games makes me think that he believes he'll find little relief there. Which is fine, until we get to later in the season, when the rotation may be a bit more ragged after throwing so many pitches.

With eight wins banked, the Tigers have made dramatic improvements to their playoff odds. But some of the same questions remain. The advantage gained is still dependent on things like whether Verlander can improve on last season, how much petrol the bullpen has stocked up to pour out in high-leverage situations and how efficiently Cabrera and the Latin legal firm of Martinez, Martinez & Cespedes can deliver runs.

Saturday, 21 March 2015

Looking Forward to... AL Central Relievers

The Tigers' bullpen was possibly the biggest cause of their difficult path to the AL Central championship in 2014, and to their ultimate flop in 2013. Mr Dombrowski, however, seems to have concluded that new faces aren't going to change much, so the Tigers go into 2015 with largely the same cast that proved wanting in 2014. One major change is the addition of Tom Gorzelanny. Given the comment about Brad Ausmus' trusting his veterans in this article, it seems likely that Gorzelanny is going to be given the first crack at being the premier left-hander.

For the purpose of measuring relative strengths in the bullpen, I have selected four relievers to represent each team, guessing at which four will pitch the highest-leverage innings. Using the same method I used in the post on rotations, here are the respective quartets:

In neither of the first two in this series did any team have such an advantage over the others as the Kansas City Royals have over their AL Central rivals in the bullpen. Kelvin Herrera, ranked third behind Greg Holland and Wade Davis, is as good as the best of any of the other bullpens save the White Sox' David Robertson.

The Tigers' problem is that no lead looks safe with Joe Nathan as the closer. He has been booed in Florida, which is not going to help matters, either. However, taking the Tigers' bullpen as a unit, the righty set-up men, Al Alburquerque and Joakim Soria, look a bit more solid than their equivalents on the Cleveland Indians, the Royals and the Minnesota Twins. It looks as if the Tigers' fate is going to depend a lot on how many left-handed hitters they are going to face in high-leverage situations.

Wednesday, 18 March 2015

Looking Forward to... AL Central Rotations

Mr Dombrowski's trade of Doug Fister and Max Scherzer's rejection of a $144 million contract (which, to be fair, he bettered), completely undid the excellent Tigers' rotation of 2013. The question is whether the 2015 rebuild is strong enough to carry the Tigers into the post-season, where its shortcomings might be easier to hide.

How does it stack up against the other rotations in the AL Central? Here is a chart—

The numbers are a metric of my own invention, using linear weight values for strikeouts, non-K outs, hits, home runs and walks to create a 'Pitching Runs'. The result isn't intended to be predictive of anything, but an estimate of the relative strength of each pitcher based on 2015 Steamer projections. I used six pitchers for each rotation because the fifth starter can be said not to exist.

As one can see, the Cleveland Indians' rotation is quite deep, with Corey Kluber a clear number one, and getting strong support from Carlos Carrasco and Danny Salazar. It is almost 50 per cent stronger than the Tigers' one, mostly because Justin Verlander and Anibal Sanchez are not quite as strong as the Clevelanders' #2 and #3.

Worse, from the point of view of Tigers' fans, is the way the White Sox have apparently just as good starters in Jeff Samardzija and Jose Quintana backing up their #1, Chris Sale, as the Tigers have behind David Price. However, the fall-off in the White Sox' rotation is the worst in the division. The Royals and Twins lack a true ace.

The Tigers have their work cut out for them this season, even if Justin Verlander should bounce back. Before, their rotation strength was not just individual quality, but also depth. They will need to hit more consistently this season, to make up for a weaker back half of the rotation than we would have expected in recent years.

Tuesday, 17 March 2015

Fearless Joe Sheehan Predicts #2

On 7 February 2005, the Detroit Tigers signed Magglio Ordonez to a five-year contract for $75 million, and options for 2010 and 2011. At sabermetric sites such as was largelyh hostile. To sum it up, the criticism was 'Too expensive for the likely production.' But Fearless Joe Sheehan took things a little bit further
In the short term--2005, maybe 2006--this contract should make the Tigers a better team. Even a past-peak Ordonez, if reasonably healthy, should put up a .300 EqA that will be a big improvement on recent Tigers' corner outfielders. It won't be long, though, before Ordonez's salary far outpaces his value, and eventually is used as the excuse for not retaining a Jeremy Bonderman, or an excuse for more "changes to the system."

The Tigers, though, can't blame any system, or boogeyman in the offices of the MLBPA. They walked into this one, and they will deserve what they get in return.

In fact, as far as one can tell, the Ordonez contract had no impact at all on the Tigers' willingness to spend money to retain star young players, including someone better than Magglio Ordonez