HOW
TO USE - What we have done for this week's Stat Class
101 is a bit different. Instead of taking the Top 30 teams
by weekly national ranking, we list above the top 30 in declining
order for pass defense. The left column is the teams' name
and record, with appropriate national ranking (AP) if needed
in parenthesis. The next column over (a) is the given team's
pass defense ranking. After that is (b) the team's pass efficiency
defensive rank, with (c) the run defense, and then finally
(d) its total defensive rank in the far right column.
First
thing to grasp is how the pass "efficiency" defense
is different from just pass defense. Pass defense is based
solely on a team's yardage totals. The pass defense ranking
is figured for how many yards per game are allowed through
opponents' passing efforts. Pass efficiency defense takes
not only their yardage, but pass completion percentages, both
INT total and percentage of INTs thrown, TD total and rate,
yards per attempt and yards per completion into account to
then give an overall rating. Just like yardage, the lower
your opponent's pass efficiency number, the better you are
doing. But unlike stopping just yardage, if the other guy
is mistake-free and can score via aerial assault, you are
likely going to lose. Really, you can survive a 50-yard pass
play that only gets them to your 35, but there is no "recovery
room" from an 11-yard scoring strike set up by 12 good
runs. It is good when your opponents are less efficient, even
if they get a few extra yards.
A team
can have disparaging ranks in (a) and (b) (the first two columns)
for different reasons. First, look and see how many teams,
nine, have a 30-or more rank difference between (a) and (b)
(teams marked by an asterisk - *). Notice how only one, Georgia,
is actually a ranked team. Most importantly, the No.10 Bulldogs
rank 25th (c) for run stopping (108 yards per game and 2.9
yards per carry), meaning opponents have to go to the air
early and often. The end result is a strong total defensive
rank (d) of 4th, but their marginal pass efficiency defense
(b) of 66th still means one loss. That loss (to Tennessee
10/9/04) was highlighted by the Vol's small passing yardage
total (150 yards), but two catches were for TDs and none were
for INTs - efficient enough for a 19-14 Tennessee victory.
Sean Jones, where are you?
Of the
remaining eight (*) teams, the highest run stopping ranks
(c) are 67th for Kansas State and 68th for Navy, which still
makes their overall defenses rank (d) 39th and 37th, respectively.
KSU struggles at 2-4, but they also bring the wood each and
every week in their tough conference, and Navy has but one
loss. But then for the rest, a high run stopping ranking (c)
coupled with a bottom-half (ranking lower than 60th out of
all 117 I-A teams) pass efficiency defense equals, at best,
Mississippi State's 56th total defense and their 1-5 record.
The Bulldogs may not bend that much, but, evidently, they
are often broken. In other words
pass defense yardage
is important, but not as important as pass efficiency defense
and run stopping efforts in producing both total defense and
wins. If your opponent can run all over you, then your pass
defense number/ranking can be low yet you still lose.
Still,
if you stop passing yardage (a), you are well on your way
toward a strong overall defense (d). Notice how only eight
(#) of the top 30 pass defenses (a) rank in the bottom half
for total defense (d). But of them, only UCLA is winning through
it all, and that must be due to both their strong pass (a)
and pass efficiency (b) defensive rankings. If the Bruins
ever improved their second-to-worst run stopping rank (c),
they would be right there with USC and Cal this year. (The
only way for UCLA to beat USC December 4th is if they can
first stop Reggie Bush, and any extra men in the box to do
that will be exploited through eventual passing success.)
The rest of them (#) rank no higher than 88th for run stopping
(c). Again, conclude this - if you can't initially stop the
run, neither your pass defense (a) nor your pass efficiency
defense (b) will provide enough total defense (d) to keep
you winning. As long as your opponent is efficient when throwing,
he need not get gads of yards in order to beat you.
Systematically,
the teams with no marks, either a (*) or a (#), seem to be
doing well. Penn State is the only non-marked squad with a
losing record, but the Big Ten is no picnic for a team like
PSU struggling with identity. The Nittany Lions were one TD
from possibly upsetting Purdue, which means they would now
be 3-3 and would fit this paradigm.
Bottom
Line - Balance on defense is most important. So, no matter
how high one's pass stopping ranking may be, in the end, keeping
foes from passing yards (a) alone means nothing. Also, a team
can still win having either a weak pass efficiency defense
(b) or a weak run stopping game (c), but not both.
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