Alabama by the Midseason Metrics

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 2018 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 Tennessee 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 had a loss to Clemson in the second week of the season. Missouri has a nice offense, but they’re only a game above .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 an offense ranked among the nation’s elite and a young defense that has gotten better with each passing week, 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 an SEC East champion Georgia or Florida, there’s no reason to believe that the Tide won’t be in the National Championship title game once again this year (for the fourth 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 2018. The Alabama defense is always one of the finest in the land, but this year has seen a marked regression statistically. Alabama usually ranks in the top-5 in all major defensive categories, but that’s not the case thus far in 2018.

The Tide is ranked 17th in total defense, allowing 312.8 yards per game thus far. They are the 23^rd-ranked team in rush defense, as they are allowing 118.3 yards per game on the ground (they were allowing an obscenely-low 66.4 yards per game to their opponents at the same time last season). Against the pass, the Tide ranks 33^rd in giving up 194.5 yards per game (13th in team-passing efficiency), and they boast the 12th-ranked scoring defense with only 15.1 points allowed per game.

Delving a little deeper, Alabama has had a lot of success rushing the passer this season. The Tide now has 26 sacks on the season (they had 23 at this point last year), good for 10^th amongst FBS teams. The tackle for loss numbers also rank in the top-50 nationally, as the Tide has 62 tackles for loss (54 midway through 2017), good for 19^th. The Tide has proven itself a turnover machine in the first half of the season, with 17 total turnovers and a margin of +11, which makes them the sixth best team in turnover margin.

Alabama’s defense has also performed well in situations that apply pressure to the average defense. The Tide ranks 12^th nationally in third-down defense, allowing conversions in a little more than one of every four attempts (.298). Bama is nearly as efficient in the red zone, where they’re tied for 12^th, allowing a score on only 72.7 percent of attempts inside the 20-yard line.

While the Tide defense is always dominant, the hammer of the Tide team this season has been the performance of the Bama offense. They’ve been both efficient and explosive, mounting a fearsome aerial attack led by Tua Tagovailoa that is punctuated with big-play ability at receiver and tight end.

Alabama is ranked first in total offense, gaining 564.3 yards per game in 2018. The lofty ranking comes largely due to a phenomenal passing attack of Tagovailoa, and a stable of elite receivers such as Henry Ruggs III, Devonta Smith, Jerry Jeudy, Jaylen Waddle, and Irv Smith Jr. With the offensive line working as a cohesive unit, the Bama ground game has been effective when it is used, with the Tide generating 216.9 yards per game on the ground, good for 29^th nationally (and 5.23 yards per carry). Alabama’s passing stats are impressive, as the Tide is ranked fifth in passing yards with 347.38 yards per game. The Tide still has the nation’s best scoring offense, averaging 54.13 yards per game (almost six points more per game than second-ranked Houston).

Alabama has been dynamic on third down, ranked first in third-down conversions with a conversion rate of 56.18 percent, though they rank 77^th in red zone offense with an 83 percent score rate. In positive yards per pass completion, Alabama is second with 18.78 yards per catch.

Alabama’s offensive line has rallied well after a few rough outings early on, and that is borne out statistically. Alabama is fifth nationally in sacks allowed with a mere five total sacks given up all season (they had allowed 11 by this time last year). They are eighth in tackles for loss allowed with 33 total.

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 www.footballoutsiders.com 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 second in success rate. 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 108th in IsoPPP+, meaning the Tide gives up a ton of explosive plays to opponents, which could be considered evidence that Alabama has a good, but not elite, defense.

The Bama defense is the 20^th-ranked team in all the land in defensive S&P+, which would be impressive for any team that doesn’t boast Alabama’s traditionally great defensive pedigree. Breaking that stat down further, Alabama is ranked 14^th in rush defense S&P+, fifth in pass defense S&P+, 11^th in passing down S&P+ (defined as second down and 8+ yards to go, or third/ fourth downs with 5+ yards to go), and 12^th in Standard Down S&P+ (standard downs are all downs not considered passing downs). These stats paint a very accurate image of a strong defense with a few key weaknesses: the Tide is solid against the run, aggressive and opportunistic against the pass, but exploitable with explosive plays.

Another great metric that helps to illuminate the Tide’s defensive 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 second (it was third at this point last season) in overall Havoc ratings, seventh 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 Clemson’s defense can rival Alabama’s success in DFEI and its sub-metrics, as Bama and Clemson are definitely the top two units in that regard. Clemson edges Bama in the overall DFEI (the Tide is ranked second), but Alabama is first in DE, third in DDS, third in DTD, eighth in DTF, third in DAY, first in DFD, and 15^th in DTO.

One final advanced stat finishes the portrait of a potentially dominant 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. In adjusted line yards, the Tide ranks 16^th, while ranking seventh in standard down line yards (1.84 yards) and 96^th in passing down line yards (2.86 yards). Bama performs well in opportunity rate, as they rank 23^rd with 41.6 percent. However, Alabama falls a little in power success rate, ranking 26^th with a rating of 60 percent. Likewise, Alabama is out of the top-10 in stuff rate at 14^th (25.7 percent), but the Tide is fifth in adjusted sack rate, 24^th in standard down sack rate, and fourth in passing down sack rate.

These metrics accurately illustrate the Bama defense’s strengths and relative weaknesses in 2018. 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. The Tide is prone to explosive plays, but that may also be a function of the success of the offense and the early substitutions on defense as a result. As many have commented, the Tide pass rush is better this year than last, at least regarding the defensive line.

In the past, the Crimson Tide leaned heavily on its defense while demonstrating efficient, if not explosive, 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 second nationally in overall offensive S&P+, eighth in rush offense S&P+, first in passing game S&P+, second in standard down S&P+, and first in passing down S&P+. Alabama is ranked first in success rate and second in IsoPPP+.

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 first in OFEI, first in OE, first in ODS, first in OAY, first in OFD, first in OTD, first in OTF, and ninth 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 strike with both the run and pass with balance. Unlike past Bama offense that would wear opponents down with attrition, Alabama’s current offense can grind out 10-play drives or strike vertically downfield with equal aplomb. 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 third in adjusted line yards, second in standard down line yards (3.42 yards), and 23^rd in passing down line yards (3.17 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 fourth in opportunity rate, 44th in power success rate (75 percent), second in stuff rate (9.0 percent), seventh in adjusted sack rate, 22^nd in standard down sack rate (2.7), and fifth in passing down sack rate (1.8).

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 strength in pass blocking, as the line has been able to keep Tagovailoa off the grass for most of the season. The stuff rate is particularly interesting when combined with Alabama’s ranking at 23^rd 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 has its full array of offensive weapons on the table.

Bama is ranked second 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 OFEI, second in DFEI, and 40^th in SFEI. The top team in overall FEI? None other than Dabo Swinney’s Clemson.

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. The Tide leads the pack in the top slot, with Clemson, Oklahoma, Georgia, and Michigan behind them, 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 2018 National Championship. The Tide’s strength is its efficiency on both sides of the ball, which has it featured as a top-20 unit in both the offensive and defensive S&P+ statistical categories. 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 both sides of the ball, the results of the 2018 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.