Let’s do the same analysis using XmR and Sharpe charts, and see how the defense did in terms of limiting their opponents. The technical details of how to create XmR and Sharpe charts were explained in part 1.
Again, when looking at the XmR chart there are a few things to consider:
- Is there is a result above or below the red, three-sigma limit lines? If so, the game performance is out of the normal performance range for the team. Worth investigating why.
- Since we are talking about the defense, the lower the mean YPP, the better.
- Are there any trends?
- The width of the red bars. The distance from the center line (mean seasonal YPP) to the red bar is 3 times the estimated sequential standard deviation. This gives you a measure of the game-to-game variability in YPP. The wider the bars, the less consistent the performance game to game.
Looking at Figure 1 we see the following:
- There were no teams with anomaly games. The teams did not have a game that crossed the 3-sigma red lines.
- The best defense of the era was the 1996 defense. It averaged 3.22 YPP per game. The 1998 and 1997 defenses at 3.45 and 3.53 YPP per game round out the top 3. Surprisingly, the ‘93 and ‘99 squads had defenses that ranked 10th. (4.37 YPP) and 12th. (4.47 YPP) out of the 14 teams. The offenses carried the day for both squads.
- When you look to see if there are trends in performance for any of the teams you find that the 1989 team started off badly, but improved as the season went along. The 1988, 1992 and 1999 teams also improved with time. On the flip side, the 1993 did worse defensively as the season went on, as well as the ‘94 and ‘95 teams. Their performance begins to deteriorate after game 5 or so.
- The 1987 team was the most consistent game-to game of the era. The 1991, 1994 and 1996 teams round out the top 4 in terms of consistency game to game. You can see where the 1991, 1996 and 1998 teams could have won championships had it not been for the offense. The 1997 and 1999 teams were the most inconsistent game to game. One other thing that is noticeable is how the UF teams of the mid 1990’s gave FSU fits. The worst defensive performances from 1994-1997 came at the hands of the Gators.
Defensive Performance Using a Sharpe Chart
Looking at the Sharpe Chart for the defense here’s what we find:
Here, a good team does not give up many yards per play and is consistent game to game so you want to be in the bottom left hand corner. You don’t want to be in the upper right quadrant. The mean yards per play is for all of the teams since 1987. Likewise, the mean standard deviation accounts for all of the teams since 1987.
- Except for the 1989 team, all of the teams are below the average of 4.54 YPP per game for the last 32 seasons.
- All of the teams ranged between 3.2 and 4.6 YPP given up per game.
- The 1996 team stands out as being absolutely stingy and relatively consistent.
- The 1993 and 1999 defenses were at the bottom of the era’s teams in terms of yards given up and consistency game to game.