Taking a Look at Changes in Contact Rate

Back in 2009, Eric Seidman wrote a piece here that looked into when samples become reliable for certain statistics. The piece was based off work done by Pizza Cutter. You can read the piece here for a full explanation of how the conclusions were reached, but below is a list showing how many PAs it takes for a statistic to become reliable.

50 PA: Swing %
100 PA: Contact Rate
150 PA: Strikeout Rate, Line Drive Rate, Pitches/PA
200 PA: Walk Rate, Groundball Rate, GB/FB
250 PA: Flyball Rate
300 PA: Home Run Rate, HR/FB
500 PA: OBP, SLG, OPS, 1B Rate, Popup Rate
550 PA: ISO

Prior to yesterday’s games, the cut off for qualified hitters in 2013 was 99 PA. As a result, we can now look at 2013 Contact% and compare it to career rates to see who is making contact at a much higher or much lower rate so far this season.

The average gap in 2013 Contact% and career Contact% was -0.22%. The standard deviation was 3.41%. No players were two standard deviations or more above the mean, but six were two standard deviations or more below the mean. They are listed below.

Name

2013 Contact%

Career Contact%

Contact% Gap

Pedro Alvarez

62.50%

69.90%

-7.40%

Albert Pujols

78.30%

85.80%

-7.50%

Dan Uggla

64.30%

72.70%

-8.40%

Jeff Francoeur

69.40%

77.80%

-8.40%

Jason Castro

73.50%

82.20%

-8.70%

Colby Rasmus

59.20%

75.90%

-16.70%

 

This is kind of a big deal because there is a strong correlation between Contact% and K%. I did a quick regression test using the 179 hitters who had 100+ PA last year, and got an r-squared of 0.8192. Not that the relationship of those two things wasn’t obvious beforehand.

contact regression

Aside from Pujols, all of these guys were high strikeout hitters to begin with. But this is further evidence that Pujols is in full on decline mode. When I calculated average and standard deviation for the gap between 2013 Swing% and career Swing%, Pujols was one of only four players whose gap in Swing% is more than two standard deviations above the mean. In other words, not only is Pujols making 7.5% less contact, he’s also swinging at 5.8% more pitches. Not a good combination.

There were two other notable names that showed up fairly high on the “making less contact” list, slow starters B.J. Upton and Jay Bruce. Their contact percentages are down 6.5% and 4.1%, respectively. Obviously, their strikeout rates are way up, and their slash lines don’t look like they have in the past.

Of the two, you should be less worried about B.J. He’s walking more than he did last year, and his BABIP is a miniscule .209.

On the other hand, Bruce should be a serious concern. His average is right around .250 like it always is, but he has needed a .362 BABIP to keep it there. When the luck goes away and he’s left with significantly worse contact skills, the average may fall off the map. It would be tough to sell high since the power hasn’t been there and because he hasn’t even been a top 70 outfielder according to ESPN’s player rater. But if there is someone out there hoping for a rebound and still willing to pay 75 cents on the dollar, take it.

At the top of the “making more contact” list, you unsurprisingly find the names of some of the biggest surprises of the season. Nate McLouth and Matt Carpenter have the largest positive gaps between their 2013 and career contact rates at 6.3% and 6%, respectively. McLouth’s plate discipline numbers are super impressive as he has a 14% BB% and a 9.1% K%. Thanks to the increase in contact, McLouth is currently a top five outfielder per the player rater, and Carpenter has been a top ten option at both second and third base.

Both guys are also buy-high candidates. Neither one is relying on a completely unsustainable BABIP. They’re both a little above average at .315 and .316, but they aren’t going to get hit too hard by regression. If someone added them off the wire and is looking to cash in and sell high before they regress, take them up on that offer.

Mark Reynolds also shows up in 8th on the list with a 4.7% increase in Contact%. As a result, his K% is 7.3% lower than his career average. That has led to a .280 batting average (.290 BABIP) for Mark freaking Reynolds. You can’t predict ball.

Below is a list of those with a gap between their 2013 and career contact rates that is more than one standard deviation above the mean.

Name

2013 Contact%

Career Contact%

Contact% Gap

Nate McLouth

92.00%

85.70%

6.30%

Matt Carpenter

91.40%

85.40%

6.00%

Torii Hunter

82.60%

76.80%

5.80%

Chris Davis

74.40%

68.80%

5.60%

Trevor Plouffe

84.40%

79.10%

5.30%

Alfonso Soriano

79.30%

74.10%

5.20%

Mark Reynolds

68.90%

64.20%

4.70%

Lorenzo Cain

84.40%

79.70%

4.70%

Josh Rutledge

84.20%

79.50%

4.70%

Donovan Solano

89.30%

84.70%

4.60%

Jonathan Lucroy

90.40%

85.80%

4.60%

Angel Pagan

92.50%

87.90%

4.60%

James Loney

92.40%

87.90%

4.50%

Jed Lowrie

88.60%

84.20%

4.40%

Josh Donaldson

82.40%

78.00%

4.40%

Joey Votto

82.50%

78.20%

4.30%

Starling Marte

79.60%

75.40%

4.20%

Adrian Beltre

84.30%

80.10%

4.20%

Manny Machado

83.10%

78.90%

4.20%

Ben Zobrist

87.70%

83.70%

4.00%

Russell Martin

86.30%

82.30%

4.00%

Shin-Soo Choo

80.20%

76.20%

4.00%

Jayson Werth

82.10%

78.10%

4.00%

Matt Holliday

82.40%

78.40%

4.00%

Ruben Tejada

89.70%

85.90%

3.80%

Miguel Cabrera

82.80%

79.20%

3.60%

Greg Dobbs

85.50%

82.00%

3.50%

Austin Jackson

82.90%

79.40%

3.50%

Norichika Aoki

92.40%

89.00%

3.40%

John Buck

78.20%

74.80%

3.40%

Justin Morneau

84.00%

80.80%

3.20%




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You can find more of Brett's work, including his podcast, on TheFantasyFix.com or follow him on Twitter @TheRealTAL.


35 Responses to “Taking a Look at Changes in Contact Rate”

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  1. Eric says:

    What does it mean that a statistic has “become reliable”? Does it mean we should expect the contact rate of these hitters to remain about where it is for the rest of the season, or for those whose contact rate is higher than career avg. we should expect it to come back down, vice versa?

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    • Brett Talley says:

      I guess the idea is that it means we shouldn’t necessarily expect regression. Like if a guy has a .400 BABIP through 100 PA, we expect that to regress to somewhere close to his average. But if it’s “reliable” it means we’re not really talking about an anomaly and could expect to continue to see the new rate.

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      • byron says:

        No, Brett, I don’t think that’s a good explanation. I think Pizza Cutter’s work was to show the point at which a sample’s results explained 50% of subsequent variation. Even if that’s not phrased exactly right, I’m positive that there’s still a ton of regression left to do at the “stabilization” point.

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    • Frank says:

      That you’d expect the stat for the rest of the season to be closer to what it is now than what pre-season projections said.

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      • Skin Blues says:

        Here is how Tango suggests the data be used:

        “I like to get things to r=.50. You’ll see the reason in a minute. If r=.70, when PA=300, then r=.50 when PA=130. It’s not important how I got that for now.

        Ok, so what can you do with that?

        This means that you can add 130 PA of league average HR/FB to any player, to get an estimate of his true talent.”

        And to get to r=.5 he suggests multiplying the r=.7 value by 3/7. So it’s a bit of math and research to look up league averages. Pizza Cutter describes it as this: “At .70, the rate of signal to noise crosses the halfway point”. Tango’s method seems more accurate, and Pizza’s method seems quicker. Seems they’ve been arguing over which one to use for about a decade, now.

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    • Fischer says:

      Razzball’s Jaywrong wrote about this recently. If you’re looking for more analysis and explanation about what these PA benchmarks mean, I suggest checking it out.

      http://razzball.com/when-is-a-streak-not-a-streak-anymore/

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  2. Skin Blues says:

    That Sample Size page is way outdated. Pizza Cutter re-did the work last year after finding out how inaccurate the original data was (and actually he posted the updated Pitchers data table yesterday on BP).

    For instance, that Fangraphs SSS page lists LD% and K% as both stabilizing (reaching a split-half correlation of 0.7) after 150 PA. However in the new study with improved methods, LD% is actually about 850-900 PA (600 BIP) and K% is actually 60 PA. Contact% was not re-done but with how far off the other stats were, I would not assume the 100 PA figure to be accurate. I just thought I’d point this out for people that have been using that outdated page on Fangraphs.

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  3. Frank says:

    Just trying to make sure I understand what you’re trying to point out. Is Sal Perez someone to be worried about? Even though he’s in the top 50 of contact % leaders, his % is down by about 5 points and his k% is about double. His BABIP is more in line with his career avg so he would fall more into the Upton category or the Bruce category?
    Thanks

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    • Brett Talley says:

      More “Bruce” I guess because he shouldn’t see a BABIP boost like Upton soon. But Perez is different from Bruce in that he doesn’t have enough career PA for his career BABIP to be reliable. You need at least 2-3 years before BABIP is reliable.

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  4. Pops says:

    I just traded for Bruce and Torii Hunter in a keeper league. I gave up Mike Minor and Zack Wheeler, as I’m really loaded with top arms. What can we expect from Bruce ROS? Although the BABIP may fall, I’m inclined to believe that his contact rate will rise a bit as the season progresses. He’s only 26, and that skillset typically shouldn’t erode this early, should it?

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    • Brett Talley says:

      I guess the original idea for this piece was that we’re at the point where we should be concerned about a change in contact%. But given the question concerning the accuracy of the 100 PA mark for contact rate that was raised in the comments above, I think this should be viewed more as a “keep an eye on these guys” piece.

      And if you’re loaded with arms, I don’t mind that trade for you at all. Bats almost always >> arms IMO.

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    • Ian says:

      I’m on the opposite end of the spectrum for Bruce–I’ve got him in a loaded OF, and wondering if I should cut bait or wait him out. Problem is, he is the only 30+ HR threat in my lineup (unless Votto picks up his power pace). And I hate selling low.

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      • Brett Talley says:

        I’m with you. I almost never sell low. But I’m legitmately worried about him. If I was looking to deal Bruce, someone like me would actually be the perfect trading partner. What I mean is that normally I’d jump on a guy like Bruce and offer something relatively close to what he cost on draft day. So if I could find a guy looking to take advantage that will make you a reasonable offer, I’d take it.

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  5. Chcago Mark says:

    WOW! I don’t speak Russian….or mathematics. This is all tough for me. But I did a little of the old math on Chris Davis from 2012. His contact rate the first 100 ab’s was 75%. The next 100 it was 70%. The next two data points were 65% and 60%. I understand the 100 pa/ab isn’t a line drawn in the sand. But this is useful data for the discussion. The numbers aren’t exact and I may have even used the wrong calculations. But again, it’s close enough for the conversation. I think. So is he an anomaly? Or……what?

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    • Brett Talley says:

      That’s a good question. Given the concerns raised about the accuracy of the 100 PA mark mentioned by some commenters above, I’m hesitant to give much of an answer.

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      • Chcago Mark says:

        Damn them Brett. Give me/us your opinion. It is valued.

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      • Brett Talley says:

        I guess I’ll say this. I think a higher contact rate is obviously a sign of improvement and means that a guy can have a season-long contact rate higher than his career rate. However, the larger sample size is always better and more reliable so guys like Davis are probably still going to see some regression toward their career rate but can still maintain contact rate in the current season higher than their career rate, just not a whole lot higher like Davis. Hence his slide back as the year went on. But he still posted a contact rate for the year that was several percentage points higher than his career rate.

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  6. J says:

    In a ten team keeper league I traded Bruce last week for Starling Marte, Shelby Miller, Jose Fernandez, and Jon Lester. I’m very happy with that trade and think the person really overpaid for Bruce.

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  7. Steve says:

    Is Chris Davis for real? What state line would you expect from him going forward?

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  8. Tyler says:

    Any thoughts of an appropriate list of bats if you’re selling low on Pujols? Trying to shop him for a replacement at UT.

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  9. Matt says:

    What was Pujols’ contact % at this time last year?

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