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會翻譯這篇文章是因為在Yahoo上看到了"伸卡之王 數據為證"這篇新聞，翻譯完之後發現這篇新聞有兩個錯誤的地方。第一點就是，原文作者並沒有說王建民是伸卡之王，但是記者卻寫"評比結果，王建民獲得「伸卡之王」的封號"。第二點則是新聞的最後一段，記者寫說"當年戴萬（John Dewan）寫「防守聖經」（Fielding Bible），讓球迷「以為」基特是最棒的游擊手"，但是事實上「防守聖經」是說Jeter可能是大聯盟史上曾經獲得金手套，但是守備最爛的游擊手。

This is a guest post by Adam Bernfeld. He is trained as an engineer and likes to apply his analytical nature to baseball to differentiate 「what seems」 vs. 「what is」. His interests include PITCHf/x, DIPS, the concept of clutch, and Laura Posada.

這篇是來自Adam Bernfeld的文章。他是一名工程師，並且喜歡利用自己的專長來區分「似乎是」與「肯定是」。他關注於PITCHf/x，DIPS，concept of clutch與Laura Posada(Posada的老婆)。

「Statistics are like women: mirrors of purest virtue and truth, or like whores to use as one pleases.」
-Theodor Billroth

「統計數據有時可以反映出真實性，有時卻可依照個人觀點來使用。」- Theodor Billroth

It is true that in a vacuum, statistics are almost entirely useless. One can manipulate the numbers to prove any side of an argument. They can however provide illumination in instances where what seems may differ from what is. For example, a few years ago before John Dewan wrote the Fielding Bible, a lot of Yankee fans truly did believe that Derek Jeter was a good defensive shortstop because he both seemed like a good fielder, and our broadcasters told us that he was a good fielder. Similarly, watching a Yankee game, one could be led to believe that Chien-Ming Wang possesses the best sinker in all of baseball. After all, it is 94 miles-per-hour and looks like it is dropping off a cliff. Surely no one's could be better, right? Well, using PITCHf/x data, I hope to crown the true 「Sultan of Sink.」

事實上在個案中，統計數據幾乎是完全沒有用的。任何人都可以巧妙的運用數字，甚至舉例子來解釋似是而非的論點。例如，幾年前在John Dewan的著作Fielding Bible完成之前，許多洋基迷確信Derek Jeter是一名防守優異的游擊手，因為他看起來似乎是個好的守備員，播報員也告訴我們他是一個好的防守者。同樣地，觀賞洋基隊的比賽時，任何人都可能認 為王建民是大聯盟中最棒的伸卡球投手。畢竟他的伸卡球有94英哩的速度，而且看起來就像從懸崖掉下來似的。肯定沒有人能投的更棒，對吧?好吧，運用 PITCHf/x的資料，我希望能找出真正的「伸卡球之王」。

For those new to PITCHf/x, it is a system developed by Sportsvision in use by Major League Baseball that uses two cameras to measure the position of the baseball between the pitcher's hand and home plate, which can be used to determine various parameters about each pitch including velocity and break (for a more thorough introduction to PITCHf/x, refer here and here).

對於PITCHf/x不熟悉的人，它是一套由Sportsvision所發展的系統，並且被大聯盟所採用，這套系統使用了兩部攝影機測量球從投手出手到本壘版之間的位置，可以測定出每一球的速度與變化量等等數值(詳細介紹請參考這裡和這裡)。

Using PITHf/x data compiled by Josh Kalk of The Hardball Times, detailed pitch information can be seen for individual players or in a searchable database. For this study, I will compare the speed, horizontal break and vertical break of the average signature pitch of baseball's prominent sinkerballers from the 2007 season. Based on reputation and ground ball rates, I have chosen a test group that includes: Chien-Ming Wang, Fausto Carmona, Aaron Cook, Roy Halladay, Tim Hudson, Derek Lowe, Sergio Mitre, Brandon Webb and Jake Westbrook.

利用Hardball Times網站的Josh Kalk所蒐集的PITHf/x資料，詳細的投球資料可以從個別球員或檢索數據庫中查看。在本次的研究中，我將比較2007年球季大聯盟中主要的伸卡球投手的球速，水平變化與垂直變化的平均值。基於名氣與滾地球比例，我挑選了包含王建 民，Fausto Carmona，Aaron Cook，Roy Halladay，Tim Hudson，Derek Lowe，Sergio Mitre，Brandon Webb與Jake Westbrook。

Note in the chart above that the values for break represent the number of inches that the pitch moves compared to a pitch thrown without spin, or, compared to a straight pitch under only the influence of gravity. The negative numbers for horizontal break indicate that the pitch moves inside to right-handed hitters. The positive values for vertical break indicate that the pitch crosses the plate higher than a pitch without spin would have. This may seem counterintuitive as we are talking about sinkers, but in reality sinkers are thrown with backspin and do rise (resist dropping actually), albeit much less than a 4-seam fastball, so they do in fact appear to sink. A 4-seam fastball is gripped across the seams resulting in more backspin than a sinker (or 2-seam fastball) which is gripped along the seams; the more backspin, the larger the positive vertical break. For comparison, Joba Chamberlain's fastball has a vertical break of 11.42 inches, compared to the average vertical break of 4.66 for our sinkerballer group.

注意到上圖中的變化量(break)是指與沒有旋轉的球或是只受重力影響的直球比較之下的移動量。水平變化中的負數代表球往右打者移動。垂直變化的正數則代 表伸卡球經過本壘版時的高度比沒有旋轉的球來的高。這似乎和我們所談論的伸卡球相反，但是事實上伸卡球是反轉的而且會上飄(實際上是抵抗落下)，儘管跟四 縫線速球相比少得多，所以看起來會下沉。由於四縫線快速球的握法跨過縫線，所以與沿著縫線握球的伸卡球(或是二縫線速球)相比會造成較多的反轉;反轉越 多，正向的垂直變化越大。相較之下，Joba Chamberlain的快速球有11.42吋的垂直變化，而我們的伸卡球投手群平均變化量則是4.66吋。

The chart above can be shown graphically by plotting horizontal break on the x-axis and vertical break on the y-axis with pitch speed represented by dot size. In this graph, the lower right hand corner, the point (0,0), represents a pitch thrown without spin.

上圖以圖形化顯示，X軸代表橫向變化，Y軸代表垂直變化，圓點的大小則代表球速。在這張圖中，越接近右下角(0,0)這點，表示球的旋轉越少。

In hopes to build some sort of consensus as to who possesses the best sinker, I used the three PITCHf/x values (speed, horizontal break, vertical break) to create a z-score (also called a 「standard score」) which is a statistical quantity used to combine multiple values measured on different scales. I then ordered the average z-score of each pitcher from high to low to rank the pitcher with the best combination of speed and break. Think of this as an index of the 「stuff」 on the pitcher's sinker, or a 「sinker-stuff index」. This value appears on the chart below alongside each pitcher's groundball to flyball ratio (GB/FB), swing and miss (S&M) percentage, fair ball (FB) hit percentage, and fair ball extra base hit (XBH) percentage. All of these values are for sinkers only, except GB/FB which is the rate for all pitches thrown regardless of type.

為了找出誰是最佳的伸卡球投手，我使用了三個PITCHf/x數值(速度，水平變化，垂直變化)以建立Z值(又稱為「標準值」)，這個統計值結合由數個標準測量出來的數據。我將結合了每位投手的球速與變化量的平均Z值由高到低排列出來。我們可以將之視為「球威」的 指標。這個值與投手的滾飛比(GB/FB)，揮空(S&M)率，球被有效擊中(FB)的比率，與球被有效擊中形成長打(XBH)的比率一同列在下 圖中。除了滾飛比(GB/FB)以外，所有的這些數據都是只統計伸卡球。

The results of this study are interesting. While throwing one of the harder sinkers in the league (second only to Fausto Carmona), Chien-Ming Wang's sinker actually sinks less than any other member of the test group. This is certainly a surprising observation. In fact, his sinker also has the lowest horizontal break, causing his sinker to rank 8th out of 9 in my sinker-stuff index. This certainly manifests itself in his below average groundball to flyball ratio and sinker swing and miss percentage. Remarkably however, compared to the test group Wang has the lowest percentage of hits off of sinkers, and by far the lowest percentage of extra base hits off of sinkers.

這個研究的結果很有趣。雖然王建民能投出大聯盟速度最快的伸卡球之一(僅次於Fausto Carmona)，但是事實上他的伸卡球和其他的研究對象相比下沉幅度的比較小。這無疑是一個令人感到意外的發現。王建民的伸卡球水平變化量最小，也使得 他的伸卡球球威在九個人中排名第八。這也顯示在低於平均的滾飛比與伸卡球揮空率。然而與研究對象的其他投手相比，很顯然的，王建民的伸卡球擁有最低的被有效擊中率與被長打率。

While some may chalk these low hit percentages up to luck, it appears that something deeper may be happening here. Finally though, the stats are pointing towards something that we already believed to be true. What seems agrees with what is, and that is the fact that Chien-Ming Wang rarely allows a hard hit ball off of his sinker. Why then, is his sinker so successful in spite of the fact that it moves so much less than those of his peers? Maybe my methods are all wrong (I hope not). Maybe pitch speed is more significant than pitch break (possibly). Maybe the ease of his delivery, which also includes a pronounced, varied hesitation, has a great effect on hitters' timing (possible). Maybe Wang's defense is better at turning batted balls into outs than the others on this list (unlikely). Maybe the DIPS people are right and hit percentages are no more than statistical variations (possibly, although I believe that DIPS applies more loosely to sinkerballers). Maybe it is a combination of all of these factors or even something that I have not thought of (likely), so please feel free to throw out explanations of your own.

當有些人將這些較低的有效擊中率歸因於好運時，也許還有些東西需要討論。最後雖然統計資料指出某些我們相信的事是確實的。事實上王建民很少備有打有效擊中他的伸卡球，儘管變化幅度不如其他人，為什麼他伸卡球仍然投的如此成功?也許我的評估方法全部都錯了(我希望不是)。也許球速比變化幅度更為重要(有可能)。也許他從容不迫的投球影響了打者的揮棒時機(有可能)。也許在防守方面，王建民在將被擊出的球轉換成出局數上比其他人厲害(不大可能)。也許強調DIPS的人是對的，而被打擊率只是統計變數而已(有可能，雖然我相信DIPS運用在身卡球投手身上比較不嚴謹)。也許是所有因素的組合，或是還有我沒有考慮到的地方 (不大可能)，所以請隨意的提出你的見解。

Regardless of the reasons, I am glad that Wang is a Yankee as he gives us a very good chance to win once every five days. While his low ranking in my sinker index does not correlate with his outstanding results, at the end of the day I'll always take the results over the 「stuff」. Though after much machination, I have not definitively proved where Wang's sinker ranks amongst his brethren, but I hope that this was interesting and informative, and maybe allows you to view the game and the sinker in a different light the next time the Wanger takes the hill.

不管這些推論如何，我很高興王建民是洋基球員，並且有很大的機會每五天能贏一場球。雖然他在我的伸卡球指標中排名較低，但是這和他出色的表現一點關係也沒 有，最後我會以成績取代「球威」。儘管經過了一連串的比較，最後我仍然沒有證明王建民的伸卡球在眾伸卡球投手中的排名，但是我希望這次的研究是有趣與有益的，也許能讓你在王建民下次上場時從不同的角度觀賞比賽。

原文

This entry was posted on 星期四, 五月 15th, 2008 at 08:52:49 and is filed under Baseball. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.