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The Alabama, by the Mid-Season Metrics

Alabama is number one in the polls and an odds-on favorite to return to the College Football Playoffs. But are they really as good as they look? The metrics tell the tale…

Tennessee v Alabama
While Bama’s defense always fairs well in the metrics, the Tide offense powered by a running game that features Damien Harris, has been impressive.
Photo by Kevin C. Cox/Getty Images

There’s no question that the Alabama Crimson Tide has been one of the most impressive teams in all of college football over the first half of the 2017 season. They’ve not only won all eight of their games, including victories over ranked teams, but they’ve done it in dominating fashion. They throttled the likes of Ole Miss and Vanderbilt, and have beaten better teams like Texas A&M handily without the results ever being in doubt.

But there are always questions that diminish the luster of a team like the Tide in the first half of any season. Have they really played any complete teams thus far? One could argue that the Aggies are the most complete team the Tide has played to date, but they opened the season with a bad loss to UCLA. When Bama opened the season against Florida State, the now-downtrodden Noles were a formidable top-three team in most polls, though they’ve since fallen out of the top-25 and are currently under .500. So are Bama’s impressive wins really not that impressive?

One could argue that Alabama has thrived off the mediocre also-rans that seem to abound in the SEC West this season. After all, the meat of the SEC West competition remains ahead, as Alabama will endure a three-game stretch that includes the three best teams not wearing crimson in the division: LSU, Mississippi State, and Auburn. Those contests will help paint a better portrait of the Tide’s true power, to be sure.

To get a clearer picture of the Tide’s performance to date, one can look to the beacon of metrics to determine success relative to the balance of college football programs this year. Raw stats can be illuminating, but it is the advanced metrics that can truly provide a glimpse of just how efficient Alabama has been in dispatching opponents to date.

In short, whether one looks at the raw data or the advanced metrics, Alabama appears to be the monster everyone thought they’d be coming into the season. With a defense once again ranked among the nation’s elite and an offense that has been shockingly prolific, the Tide is the cream of college football: a power that seems almost unstoppable by any team not wearing crimson and white. If Alabama can navigate the final three contests of note left in the regular season and triumph over likely SEC East champion Georgia (an apparently tall task if the metrics are to be trusted), there’s no reason to believe that the Tide won’t be in the National Championship title game once again this year (for the third year running).

Unweighted Stats

Before the development of advanced metrics for college football in the 2000s, the NCAA rankings (based strictly on unweighted statistical data) were all football geeks had to help judge the performance of their teams relative to other squads. The raw metrics offered a glimpse of what a team was capable of accomplishing, but there were issues with using them for legitimate analysis.

For example, strength of schedule is not a factor in the NCAA rankings. Therefore, teams that play weak schedules can pile up stats against sub-par teams and appear far more dominant than they would ever be against better competition. Likewise, garbage time stats are not mitigated at all. Teams get the same amount of credit for 60-0 mismatch wins that were never in doubt as they do if they’d amassed those stats against legitimate, quality defenses.

However, for the sake of painting the portrait of Bama’s season to date in broad strokes, let’s look at some of the unweighted statistics, and where Alabama places amongst other teams in 2017. The Alabama defense is always one of the finest in the land, and that is no different this year. The Tide is ranked number one in total defense, allowing a mere 236 yards per game thus far. They are also the top-ranked team in rush defense, as they are allowing an obscenely-low 66.4 yards per carry to their struggling opponents. Against the pass, the Tide ranks 10th in giving up 169.6 yards per game (seventh in team-passing efficiency), and they boast the second-ranked scoring defense with only 9.8 points allowed per game.

Delving a little deeper, Alabama has overcome a slow start in rushing the passer due to numerous injuries at key positions in the front seven. The Tide now has 23 sacks on the season (2.88 per game), good for 22nd amongst FBS teams. The tackle for loss numbers also rank in the top-50 nationally, as the Tide has 54 tackles for loss (6.8 per game), good for 42nd. The Tide has proven itself a turnover machine in the first half of the season, with 15 total turnovers (11 interceptions and four fumble recoveries) and a margin of +10, which makes them the ninth best team in turnover margin. Bama’s 11 interceptions ranks seventh nationally, as they average 1.25 per game.

Alabama’s defense has also performed well in situations that apply pressure to the average defense. The Tide ranks sixth nationally in third-down defense, allowing conversions in only one of every four attempts (.250). Bama is nearly as efficient in the red zone, where they’re tied for 10th, allowing a score on only 68.8 percent of attempts inside the 20-yard line.

While the Tide defense is always dominant, the true surprise this season (to some, at least…it’s hard to glance at the Bama offensive roster and expect anything but explosiveness) has been the performance of the Bama offense. They’ve been both efficient and explosive, mounting a fearsome ground game that is punctuated with big-play ability at receiver and tight end.

Alabama is ranked 12th in total offense, gaining 499.8 yards per game in 2017. The lofty ranking comes largely due to a phenomenal rushing attack led by quarterback Jalen Hurts, and a stable of running backs such as Damien Harris, Bo Scarbrough, Josh Jacobs, and Najee Harris. With the offensive line working as a cohesive unit, the Bama ground game has been nearly unstoppable, with the Tide generating 298.8 yards per game on the ground, good for eighth nationally. Alabama’s passing stats are not super impressive, as the Tide is ranked 87th with only 201 yards per game, but the passing game has not been a necessity given the prolific nature of the running game. Despite the lagging air attack, the Tide still has the nation’s sixth best scoring offense, averaging 43 yards per game (and scoring more than 60 against two separate opponents this season).

In the niche statistics, Alabama falls slightly behind other programs, but still ranks squarely in the top-50. Alabama is 43rd in third-down conversions with a conversion rate of 43.4 percent, though they rank 23rd in red zone offense with a 90.5 percent score rate. In positive yards per pass completion, Alabama is 46th with a 13.01 yards per catch rate.

Alabama’s previously-maligned offensive line has rallied well after a few rough outings early on, and that is borne out statistically. Alabama is tied for 26th nationally in sacks allowed with 11 total sacks given up, or 1.38 per game. They are fifth in tackles for loss allowed with 27 total, or 3.38 per game.

Advanced Metrics

While the raw data and NCAA record book rankings are fun to examine, it’s the advanced metrics compiled by the likes of that tell the true story. If you haven’t given the site a look-see, it’s an absolute must in predicting trends in college football and ranking opponents using quality, weighted data that accounts for things like garbage time yardage, opponent strength, strength of schedule, and other factors that routinely skew the NCAA rankings.

First, let’s look at the defensive metrics, with a brief explanation of how they work. Possibly the most used advanced metrics in determining overall quality of a unit are the S&P+ measurements. The S&P+ ratings are derived from play-by-play data over the course of an entire season (which includes over 800 games, and over 140,000 plays, providing an excellent body of data from which to draw conclusions). Garbage-time success and strength of opponent are factored in, as each team’s output is compared to the expected output based on opponent schedule. Also, the ratings deal with garbage-time by filtering out plays run when the game was no longer competitive, defined as games with scores within 28 points in the first quarter, 24 in the second, 21 in the third, and 16 in the fourth.

These S&P+ ratings are based on the Five Factors: efficiency, explosiveness, field position, finished drives, and turnovers. As any football observer can recognize, those are the criteria upon which quality football teams are judged, as failure to perform in any of those measures can indicate a team is not a championship contender.

Those Five Factors are explained by several individualized metrics. For example, success rate measures efficiency by determining if every play an offense runs is effective or not. Success is defined as gaining 50 percent of necessary yardage on first down, 70 percent on second down, and 100 percent on third and/ or fourth downs. Defensively, the Tide is ranked fifth in success rate, with TCU being the top-ranked team in that metric. That translates to an Alabama defense that doesn’t give up many first downs, keeps opposing offenses behind the chains, and limits offensive play calling by keeping offenses in deficit situations across the course of multiple series.

IsoPPP+ is a metric used to rank explosiveness by assigning a point value to every yard line based on the number of points a team is expected to score from that yard line. It looks at only the per-play value of successful plays (as defined above), and is used to separate the explosiveness and success rate metrics. Alabama’s D is ranked second in IsoPPP+, meaning the Tide gives up very few explosive plays to opponents, a key indicator of an elite defense.

The Bama defense is the top-ranked team in all the land in defensive S&P+, which is impressive to say the least. Breaking that stat down further, Alabama is ranked second in rush defense S&P+, fifth in pass defense S&P+, first in passing down S&P+ (defined as second down and 8+ yards to go, or third/ fourth downs with 5+ yards to go), and fourth in Standard Down S&P+ (standard downs are all downs not considered passing downs). These stats paint a very accurate image of an absolutely oppressive defense with no real weakness: the Tide is smothering against the run, aggressive and opportunistic against the pass, and unexploitable with explosive plays.

Another great metric that helps to explain the Tide’s dominant defense is the Havoc rating. Havoc ratings are compiled by combining a team’s total tackles for loss, passes defensed, and forced fumbles divided by the total number of plays defensed. Havoc provides an image of in keeping with what the name implies: the ability of a team to wreak havoc on an opposing offense and keep it on its heels. Havoc ratings are delivered as an amalgam, as well as divided into front seven Havoc and defensive back havoc ratings. Alabama thrives in all three, as the Tide is ranked third in overall Havoc ratings, 10th in front seven Havoc, and fourth in defensive back Havoc. Again, there is no weak spot when it comes to Alabama’s ability to raise hell versus opponent offenses, as they provide a full-spectrum threat to any team regardless of whether they elect to run or pass.

Another primary advanced metric used to evaluate team quality is the FEI rating. Defensive FEI (or Fremeau Efficiency Index) ratings are opponent-adjusted efficiency metrics that filter out first-half clock killing plays and end-game garbage time plays. They are built using a number of sub-metrics. Drive efficiency (DE) is the value per drive of an opposing offense’s success adjusted for starting field position. DFEI is defensive efficiency adjusted for strength of opposing offenses faced. DDS is the percentage of opposing offenses’ drives that generate greater value than starting field position would generally indicate. DAY is total yards allowed by a defense divided by the number of yards available to an offense based on starting field position. DFD is the percentage of opposing drives that result in a touchdown or at least one first down. DTD is the percentage of TDs surrendered on opponent drives that earn at least one first down. DTO is the percentage of opponent drives that result in a fumble or interception.

Bama’s defense fares well regarding these advanced stats, as can be expected. In fact, only Georgia’s defense, led by former Tide defensive coordinator Kirby Smart, can rival Alabama’s success in DFEI and its sub-metrics, as Bama and Georgia are definitely the top two units in that regard. UGA edges Bama in the overall DFEI, but Alabama is first in DE, DDS, DTD, and DTF. The Tide is second to Georgia in DAY, fourth in DFD (Michigan is number one), and 49th in DTO (Wyoming is first).

One final advanced stat finishes the portrait of a dominant, devastating Alabama defense: the Defensive Line ratings. The line ratings (both defensive and offensive) are based on a number of fine-tuned criteria. Adjusted line yards is an opponent-adjusted measure of the number of yards gained/ ceded by a line portrayed on a scale of 100.0 (below 100 is bad, above 100 is good). Standard down line yards is an unadjusted measure of per-carry line yards for a team on standard downs. Passing down line yards per carry is the same unadjusted measure as the standard down version, only it is measured on the above-defined passing downs. Opportunity rate is the percentage of carries (when at least five yards are available) that a line gains five yards per carry. Power success rate is the percentage of third- and fourth-down carry (when there are two or yards left to go) that generate a first-down or touchdown. Stuff rate is the percentage of carries that running backs are stopped at or behind the line of scrimmage. Adjusted sack rate is an opponent-adjusted version of the sack rate in which the number of sacks is divided by sacks plus the number of passes. The standard down sack rate is the unadjusted sack rate on standard downs, while the passing down sack rate is the sack rate when an offense faces a passing down.

While Alabama’s current rankings regarding defensive line metrics may not be as impressive as some of the other advanced stats, it does indicate what many expected this season: specifically, that Alabama’s overall defensive line performance would take a step back after the departure of some legendary Tide defenders up front. While Alabama has generated pressure, it hasn’t necessarily been because of defensive line play, which is evident in the advanced metrics. In adjusted line yards, the Tide ranks fourth (140.2 yards), while ranking seventh in standard down line yards (2.18 yards) and 12th in passing down line yards (2.04 yards). Bama performs well in opportunity rate, as they rank third with 26.7 percent. However, Alabama falls a little in power success rate, ranking 41st with a rating of 63.6 percent. Likewise, Alabama is well out of the top-10 in stuff rate at 30th (23.7 percent), and the Tide is 51st in adjusted sack rate, 52nd in standard down sack rate, and 36th in passing down sack rate.

These metrics accurately illustrate the Bama defense’s strengths and relative weaknesses in 2017. The Tide is ferocious when it can get offenses behind the pitch count in a given series, providing numerous down-and-distance situations. Bama’s line is good against offenses on standard downs, but gives up a little ground in short yardage situations. And, as many have commented, the Tide pass rush is diminished from the past two seasons, at least regarding the defensive line, as much of the pressure defensive coordinator Jeremy Pruitt has gotten this year has come from blitzes off the edge from corners, safeties, and linebackers rather than defensive linemen.

In the past, the Crimson Tide leaned heavily on its defense while demonstrating efficient, if inexplosive, offensive output. This year, however, the Bama offense rivals the defense in its ability to take over games and dominate opponents, as the advanced metrics indicate.

Alabama is ranked 13th national in overall offensive S&P+ (37.8), 30th in rush offense S&P+ (118.2), fifth in passing game S&P+ (140.0), 15th in standard down S&P+ (123.8) and 31st in passing down S&P+ (121.6). Alabama is ranked 14th in success rate (122.2) and 15th in IsoPPP+ (129.3).

Offensive FEI is calculated in a similar way to its defensive counterpart, but there are different terms used in the specific sub-metrics. OFEI is offensive efficiency adjusted for strength of opposing defenses faced. OE is an offensive efficiency value generated per drive for offenses that is adjusted for field position. ODS is the percentage of drives that generate a value greater than that expected based on starting field position. OAY is the total number of yards earned by an offense divided by the number of yards available on a drive based on starting field position. OFD is the percentage of drives that result in a touchdown or at least one first down. OTD is the percentage of drives that result in a touchdown. OTF is the percentage of drives that end in a touchdown after at least one first down. OTO is the percentage of drives that result in a fumble or interception.

Alabama is seventh in OFEI, sixth in OE, seventh in ODS, sixth in OAY, 13th in OFD, fifth in OTD, sixth in OTF, and first in OTO. What do these stats say about the Alabama offense? In short, they are indicative of a highly efficient, explosive offense that finishes its drives and sustains series without turnovers or negative plays. Defenses have trouble limiting the Tide on early downs, and as a result, Alabama can stick with its run-first philosophy and wear opponents down with attrition. The relatively high ranking in IsoPPP+ also indicates that despite Alabama’s dominance on standard downs, the Tide also has a penchant for explosive plays that can sway games early on, a factor which has been responsible for early leads in the Tide’s contests this season.

Just as the defensive line is broken out and examined by the adjusted line yards family of metrics, the offensive line can be judged by the same criteria. Alabama’s offensive success can largely be pinned on the development of the offensive line over the last several games, as they’ve performed admirably with a simplified scheme that lets the athletes play a physical, devastating style of football that few teams can stop.

Alabama’s O line is ranked 23rd in adjusted line yards (117.6 yards), third in standard down line yards (3.7 yards), and 45th in passing down line yards (3.54 yards). This indicates that Alabama runs the ball well on standard downs, and asserts its will at the point of attack. Keep in mind, these measures are adjusted to filter out garbage time, and many of Alabama’s games thus far have featured at least a half of garbage time by the above definition.

The line is ranked sixth in opportunity rate, 52nd in power success rate (71.4 percent), sixth in stuff rate (12.6 percent), 64th in adjusted sack rate (103.8), 116th in standard down sack rate (8.7), and 59th in passing down sack rate (6.4).

What does this say about the offensive line? It says they excel at run blocking on standard downs, as some of the other metrics have indicated. It also reveals something of a weakness in pass blocking, however, though admittedly the Tide shows a decided preference for the ground attack, thus limiting the passing game sample size. The stuff rate is particularly interesting when combined with Alabama’s number five ranking in the raw TFL data, as the O line is doing a solid job of preventing opposing defenses from making plays in the back field and putting the Tide offense in down-and-distance situations. That can’t be underestimated as a critical component of Bama’s offensive success, as the offense thrives when it is allowed free reign on standard downs, when it’s potent running game can be most lethal.

Bama is ranked fifth in overall FEI, which combines Game Efficiency (GE), offensive FEI (OFEI), defensive FEI (DFEI), and Special Teams Efficiency (STE) into an overall rating. The Tide is rated first in Game Efficiency, seventh in OFEI, second in DFEI, and 13th in STE. The top team in overall FEI? None other than Kirby Smart’s Georgia.

One final super-metric combines several other major measurables to create a power ranking of sorts that can be used to establish a hierarchy among college football’s elite teams. The F/+ is a proxy ranking system that combines a team’s conglomerate S&P+ and FEI ratings into a cohesive measurement of overall team power. Surprisingly, the top five teams in the F/+ are no strangers to the AP top-five, with Ohio State at number one, Bama at two, and Georgia, Penn State, and TCU filling out the remainder, respectively.

While the product on the field for Alabama has passed the eye test thus far this season, the various metrics also back up the supposition that the Tide is once again the team to beat for the 2017 National Championship. The Tide’s strength is its efficiency on both sides of the ball, which has it featured as a top-10 unit in both the offensive and defensive statistical categories. While Ohio State gets the nod as the nation’s most powerful team in the F/+ metric, an argument could be made that Alabama is without a doubt the strongest team, top to bottom, in the nation…and they have room to grow and improve, as Nick Saban so often reminds them.

The Tide hasn’t yet met its full potential despite the thrashing of multiple opponents this season. However, if the statistical juggernaut continues on both sides of the ball, the results of the 2017 could see the Tide capture yet another coveted National Championship, cementing Saban’s place in college coaching history and adding to the dynasty he has built in Tuscaloosa over the last decade.