### Measuring the Dolphins' improvement

The Miami Dolphins were 11-5 this year, improving by 10 games over their abysmal 1-15 record in 2007. Carl Bialik wonders just how historic an improvement this was. On the one hand, he says, the improvement of 62.5 percentage points (.625) is huge. But on the other hand, there are only 16 games in the NFL season, so we're really only talking about 10 games.

Because of the shorter season, changes in winning percentages in the NFL tend to be larger than in other leagues, at least those changes that arise due to luck. For a .500 team, the standard deviation of wins in the NFL is 2 (the square root of .500 times .500 times 16). Expressed in winning percentage, that works out to .125. By comparison, it's only .039 in baseball, and .055 in basketball or hockey (ignoring the NHL's extra standings point for an overtime loss).

To get the SD of the difference between two consecutive seasons, you multiply the single-season SD by the square root of 2 (about 1.414). So a typical between-seasons luck difference would be 2.8 games. And 5% of the NFL – that's 1 or 2 teams – should have a swing of more than 5.6 games.

But it's not likely that *all* of the Dolphins' improvement is random luck. A substantial amount is probably due to better talent.

One way to check is to look, not just at the win-loss record, but at the component stats. In 2007, the Dolphins' opponents outscored them by 170 points. In 2008, the Dolphins actually scored more than the opposition, by 28 points.

According to "The Hidden Game of Football," by Bob Carroll, Pete Palmer, and John Thorn, it takes about 36 points to turn a loss into a win. That means the Dolphins "should have" been about 3-13 last year, and 9-7 this year. By that standard, they were 2 games unlucky last year, and 2 games lucky this year. (That four game swing is only about 1.4 standard deviations, which is nothing special.) This means that their talent improved by six games: 1-15 last year, plus 2 games luck last year, plus 2 games luck this year, plus 6 games skill difference, adds up to 11-5.

You can drill down even deeper – instead of points, you can look at yards gained and allowed, penalties, and turnovers. Brian Burke did that for 2007 and 2008. He found that Miami was the unluckiest team in the NFL last year, by a long shot, winning 4.4 games fewer than expected. In 2008, the Dolphins were 0.9 games lucky. That's a swing of 5.3 games due to luck, which leaves the remaining improvement of 4.7 games attributable to talent.

It makes sense that Brian found more luck with his method than just by looking at points. The total random effect can be broken up into three components:

-- players having "lucky" years by playing over their head and accumulating gaudier stats than normal;

-- teams scoring more points than you'd expect based on their stats;

-- teams winning more games than you'd expect based on their points scored.

In general, teams with extreme records, or extreme changes, are likely to rank high in each of these three categories. The "points" method counts only the third; Brian's method counts only the last two. It's likely that if you had a method of looking at the individual players, both years, you'd find even more luck. I have no way of knowing for sure, but if I had to give a best estimate, I'd say the Dolphins' 11-game renaissance looks like about 6 games luck, and 5 games skill.

## 6 Comments:

What about strength of schedule?

Oh, geez, forgot about strength of schedule. That would be included under "talent", so read "talent" as "talent and schedule."

Thanks.

Hmm, I would actually include strength of schedule under "luck", as it relates more to the luck of who NFL schedules you to play, rather than the actual "real" improvement in the team. It's this effect, imo, that is responsible for so many mediocre teams making the playoffs in the NFL each year.

Sure. Then, you could break down the 11-game improvement as:

-- 6 games luck, as described in the post;

-- X games luck, as defined by you as ease of schedule;

-- 11 - 6 - X games talent improvement.

Football Outsiders said Miami improved from 4.2 Estimated Wins to 9.2.

ESTIMATED WINS uses a statistic known as "Forest Index" that emphasizes consistency as well as DVOA in the most important specific situations: red zone defense, first quarter offense, and performance in the second half when the score is close. It then projects a number of wins adjusted to a league-average schedule and a league-average rate of recovering fumbles. Teams that have had their bye week are projected as if they had played one game per week.

豆豆聊天室 aio交友愛情館 2008真情寫真 2009真情寫真 aa片免費看 捷克論壇 微風論壇 大眾論壇 plus論壇 080視訊聊天室 情色視訊交友90739 美女交友-成人聊天室 色情小說 做愛成人圖片區 豆豆色情聊天室 080豆豆聊天室 小辣妹影音交友網 台中情人聊天室 桃園星願聊天室 高雄網友聊天室 新中台灣聊天室 中部網友聊天室 嘉義之光聊天室 基隆海岸聊天室 中壢網友聊天室 南台灣聊天室 南部聊坊聊天室 台南不夜城聊天室 南部網友聊天室 屏東網友聊天室 台南網友聊天室 屏東聊坊聊天室 雲林網友聊天室 大學生BBS聊天室 網路學院聊天室 屏東夜語聊天室 孤男寡女聊天室 一網情深聊天室 心靈饗宴聊天室 流星花園聊天室 食色男女色情聊天室 真愛宣言交友聊天室 情人皇朝聊天室 上班族成人聊天室 上班族f1影音視訊聊天室 哈雷視訊聊天室 080影音視訊聊天室 38不夜城聊天室 援交聊天室080 080哈啦聊天室 台北已婚聊天室 已婚廣場聊天室 夢幻家族聊天室 摸摸扣扣同學會聊天室 520情色聊天室 QQ成人交友聊天室 免費視訊網愛聊天室 愛情公寓免費聊天室 拉子性愛聊天室 柔情網友聊天室 哈啦影音交友網 哈啦影音視訊聊天室 櫻井莉亞三點全露寫真集 123上班族聊天室 尋夢園上班族聊天室 成人聊天室上班族 080上班族聊天室 6k聊天室 粉紅豆豆聊天室 080豆豆聊天網 新豆豆聊天室 080聊天室 免費音樂試聽 流行音樂試聽 免費aa片試看A片 免費a長片線上看 色情貼影片 免費a長片 本土成人貼圖站 大台灣情色網 台灣男人幫論壇 A圖網 嘟嘟成人電影網 火辣春夢貼圖網 情色貼圖俱樂部 台灣成人電影 絲襪美腿樂園 18美女貼圖區 柔情聊天網 707網愛聊天室聯盟 台北69色情貼圖區 38女孩情色網 台灣映像館 波波成人情色網站 美女成人貼圖區 無碼貼圖力量 色妹妹性愛貼圖區 日本女優貼圖網 日本美少女貼圖區 亞洲風暴情色貼圖網 哈啦聊天室 美少女自拍貼圖 辣妹成人情色網 台北女孩情色網 辣手貼圖情色網 AV無碼女優影片 男女情色寫真貼圖 a片天使俱樂部 萍水相逢遊戲區 平水相逢遊戲區 免費視訊交友90739 免費視訊聊天 辣妹視訊 - 影音聊天網 080視訊聊天室 日本美女肛交 美女工廠貼圖區 百分百貼圖區 亞洲成人電影情色網 台灣本土自拍貼圖網 麻辣貼圖情色網 好色客成人圖片貼圖區 711成人AV貼圖區 台灣美女貼圖區 筱萱成人論壇 咪咪情色貼圖區 momokoko同學會視訊 kk272視訊 情色文學小站 成人情色貼圖區 嘟嘟成人網 嘟嘟情人色網 - 貼圖區 免費色情a片下載 台灣情色論壇 成人影片分享 免費視訊聊天區 微風 成人 論壇 kiss文學區 taiwankiss文學區

Post a Comment

<< Home