## Saturday, March 15, 2008

One of my favorite set of posts from last offseason was the conference recap using SDPI. SDPI is a statistic I borrowed from Eddie Epstein that he used in his book, Dominance, to rank pro football's all-time greatest teams. SDPI stands for Standard Deviation Power Index and looks at how teams performed relative to the league average (or conference average in this case) and standard deviation in terms of points scored and allowed. The more standard deviations a team is above the mean, the better they are, and vice-versa. Here is the link to last year's Mountain West post. As you can see, SDPI was a useful tool in predicting some of the rise and fall among the Mountain West's teams. In the interest of providing an even better offseason analysis, I will now be conducting another SDPI, this time for yardage. It is calculated in the same manner as the SDPI for points, but will obviously be measured against the conference mean and standard deviation for yards. Think of it this way: Points are the end result and yards are the means to that end. Thus, looking at both sets of data, we can get an even better idea about which teams are likely to improve or regress in 2008.

If you want the meat of the article, skip this next paragraph as it just gives an example of how the SDPI is calculated. The mean points scored and allowed for all Mountain West teams in conference play was 187.44 points. The standard deviation for points scored was 39.02. The standard deviation for points allowed was 55.02. Air Force scored 228 points in Mountain West play and allowed 164. Their offensive SDPI was 1.04 = ([228-187.44]/39.02). Their defensive SDPI was 0.43 = ([187.44-164]/55.02). Their total SDPI for points (SDPIP) was 1.47 which ranked 2nd in the conference. The mean yardage for and against for all Mountain West teams in conference play was 2912.44 yards. The standard deviation for yardage for was 383.35. The standard deviation for yards allowed was 528.98. Air Force gained 3151 yards in conference play and allowed 3260. Their offensive SDPI was 0.62 = ([3151-2912.44]/383.35). Their defensive SDPI was -0.66 = ([2912.44-3260]/528.98). Their total SDPI for yards (SDPIY) was -0.66 which ranked 4th in the conference.

To refresh your memory, here are the 2007 Mountain West Standings.

Now here are the 2007 SDPI standings.
The SDPI standings conform pretty well with the actual standings with a few exceptions. Air Force, which finished second in the conference, rates as the 4th best team (significantly below teams 1-3) in SDPIY. TCU, which finished alone in 5th place with a 4-4 conference record, actually rates as the 3rd best team in SDPIP and 2nd best in SDPIY. If you've been paying attention to the other SDPI analyses, you'll know why. Turnovers. Air Force was tops in the Mountain West with a turnover margin of +9 in conference play, while TCU was tied for 7th with a turnover margin of -5.

Best Offense: BYU 1.55 (SDPIP) and 1.78 (SDPIY)
Max Hall stepped in admirably at quarterback for the departed John Beck. Hall was 30th in the nation among qualifying quarterbacks in pass efficiency (137.71). Freshmen running back Harvey Unga also replaced a senior starter (Curtis Brown), without missing a a beat. Unga averaged over 5 yards a rush and gained 1210 yards.

Worst Offense: Wyoming -1.47 (SDPIP) and -1.47 (SDPIY)
In 2006, the Cowboys only averaged 275 yards in Mountain West play (8th of 9 teams). With 7 starters back on offense, including quarterback Karsten Sween, it looked like they could improve upon those anemic numbers. They did. Sort of. The team averaged 294 yards per game in Mountain West play, but the conference as a whole improved and the Cowboys fell to 9th.

Best Defense: Utah 1.52 (SDPIP) and 1.12 (SDPIY)
The Utes stellar defense made up for their offensive struggles (negative offensive SDPI for points and yardage).

Worst Defense: San Diego State -1.41 (SDPIP) and -1.75 (SDPIY)
The Aztecs had a middle of the pack defense (388 yards and 23.4 points per game) until their last 3 games. Against BYU, TCU, and Air Force (the top 3 teams in the Mountain West in both points and yards), the Aztecs gave up 634 yards and 49.3 points per game.

Looking ahead to next season, the prohibitive favorite should be...

BYU
The question to be answered by the Mountain West may not be who will win the conference, but rather, who will beat BYU? The Cougars have not lost a conference game since November 19th, 2005, when they fell at home to arch-rival Utah 41-34. Not only are they 16-0 since, but they have only been outgained in a game twice (in 2006 in road games against TCU and Utah). All the key skill position players return in 2008 as well as 4/5ths of the offensive line. The defense does lose a ton from the back 7 including 3 starting linebackers and the entire secondary (depending upon whom you consider a starter). Even with the personnel losses on defense, the offense may be able to outscore teams (think the 2001 team) and keep BYU not only in the Mountain West hunt, but the also the hunt for a BCS bid. If BYU doesn't win the conference, their appears to be only one other team that can. We'll get to them shortly.

The team(s) that will improve are...

TCU, UNLV, and Wyoming