GT Volleyball: What the Advanced Stats Tell Us

From the eye test, there’s complete agreement in the volleyball world that #10 Georgia Tech is a powerful team that can beat anybody in the NCAA. The team cracked the top 5 for a week before settling back into a comfy #10 spot for multiple week. Of the two NCAA Committee Top 10 Rankings that have come out, Tech was left out both times.

The ranking criteria given for the Top 10 are as such: Win/Loss Record, Strength of Schedule, Wins vs. RPI Top 10/25/50, H2H, RPI, Common Opponents, and Record in last 10 matches. Outside of RPI, the ranking system isn’t analytics heavy by any stretch, and prioritizes wins and ways to compare the quality of wins. Considering that the college volleyball season has plenty of games in the schedule, anything beyond win-based rankings aren’t needed for anything BCS-like.

In the current state of volleyball analytics, the best resource out there right now is Husker Geek, which has advanced stats available for all divisions of NCAA Volleyball and other sports. All of the data in this piece comes from them and other metrics we were able to piece together using the data from their website. Many thanks to them for what they have going on there. I’ll note I am no statistitian or data scientist. All of what comes later is my best interpretations of the data compared to what I’ve seen on the court.

The amount of data available to glean through is extensive. To us nerds, it was a delightful time, and so we present our notable findings today to give some insights that either reveal surprising info or merely confirm what really just the eye test was needed for. While combing through the data, individual stat leaderboards did not exist beyond the top 10 in a single category, so we only compare individual stats within the team itself.

Teamwide Metrics

Let’s start with the Jackets as a team. The main metric on Husker Geek is ViPR, which they describe as “point ratings based on a calculation of each teams per set scoring efficiency. Each team’s ability to score points and their corresponding propensity to give away points is iteratively compared against their opponents and the team’s rating is adjusted.” It’s a single metric that provides a general ranking of an entire team’s performance, which is basically what the BCS computer system was doing in college football.

Tech is 12th nationally in ViPR, equally behind #20 Kentucky and ahead of #19 Washington (AVCA Rankings). The top ten are all teams except for #16 Oregon that are ranked ahead of Tech in the AVCA Coaches Poll. All things considered, this ranking feels right considering that Tech has shown incredible ability to score and defend, but still has weak moments and haven’t shown the ability to beat a top 5 team in their multiple chances this season.

Husker Geek ranks Tech’s offense the 24th best in the country, and the defense 11th. Last season with All-Americans Matti McKissock and Mariana Brambilla, they finished with the 8th best offense according to the metrics. The offensive ranking goes to show just how much Tech relies on Bergmann to keep it afloat this season. Even still, the talent in the team’s attack has lead to Tech having the 7th best opponent dig %. When Tech does attack, it’s impactful.

On the defense, what the team lacks in offense it certainly makes up for in defense. Tech is 9th nationally in digging, 10th in offensive assist %, and 11th best in allowing aces. The defense is largely bolstered by Bianca Bertolino and Paola Pimentel, the top two in digging WPA (win percentage added) on the team with a 6.32 and 7.15 respectively.

In Pimentel’s case, this is exceptionally interesting because though she leads in digging WPA, she’s committed 31 return errors. Husker Geek doesn’t have Return WPA as a specific stat, but when watching any game, it’s clear teams are targeting Pimentel, the libero and defensive specialist, with their serves. It’s a strategy that’s worked to where it’s cost Tech over a set’s worth of points so far this season.

Sets

What we’ve hinted at on Scions of the Southland that the team stats confirm is Tech’s complete dominance in the second set of matches. They’ve gone 19-2 in the second set, only losing to #5 Louisville and #7 Pitt and winning 58.72% of points, over 4% more than any other set.

Stats via Husker Geek

It’s staggering just how much better Tech plays after they a get to find their feet. Only eight times in the 21 second sets played has Tech allowed 20 or more points. We sadly don’t have set stats by player immediate to us to go further on this.

The most promising thing we found was that Tech is 6th in service points at 54.75%, the best of all the ranked teams. They have also played the fewest sets of the teams in the top 10 of that ranking. Even then, they have significantly fewer aces than the teams ahead of them. Tech when given a chance to play out a point has such a threatening attack paired with a top 10 defense that allows them to win many points they get the first ball in.

What does this tell us?

To understate it, Georgia Tech Volleyball is very good. Last year’s team may have been better, but this is not a full step down. Their teamwide rankings align closely to what the coaches have seen as well this season. Of the 31 conferences playing D1 volleyball, the ACC is ranked the fifth best behind the other Power 5 conferences. Unlike football, there is not a significant dropoff in quality after the Power 5, so the quality of the ACC is very much a blessing and a curse at the same time.

Individual Metrics

On the individual side, the reigning ACC/National Player of the Week Julia Bergmann runs the table on the offensive stats, except in serving. She has the 2nd most serves of any Jacket with 308, but has a -0.187 Serve WPA. This is a problem shared by most of the starting seven. Of them, only Bertolino and D’Amico have a positive Serve WPA. Fun fact: Erin Moss has served only once this entire season. Losing Kayla Kaiser to come in and spot serve has not aided the Jackets. Only Nicole Drewnick has a positive Serve WPA off the bench.

Bertolino is a serving and defensive strong point of this team. She has the most serves, the hightest Serve WPA, and the second best DWPA on the team behind Pimentel. Both Bertolino and Bergmann lead the team with 22 aces a piece. Bella D’Amico and Drewnick are the only players with more aces than service errors on the team. All of Pimentel, Bergmann, and Otene have given up a set’s worth of service errors but are all on track to have fewer than last season.

Pimentel is the leader in service errors right now with 31, accounting for 2.21% of all points allowed by Tech. While the returning starters are doing better on errors than last season, it still is hard to see that unenforced errors are giving even that many free points away. For elite servers, it’s a welcome gamble with how many aces come with them, but with nobody on Tech’s team with an overpowering serve, it does call to question if it’s better to let the defense do it’s job by eliminating risky serves. Again, we are not experts, just reading the numbers for what they are.

Bergmann’s usage rate each set is far more offensively than any other player, save the rare set last week where both Otene and Bergmann had 41 attacks each. She currently sits at 383 kills this season, with Erin Moss second at 169. Of points with available rallies, Bergmann is doubling Moss and everybody else on the team with how many kills she’s getting, and still is hitting above the team’s hit % (.260 to .255).

A big question we’ve wondered is what would happen if Erin Moss and Breland Morrissette got more attack opportunities? One of the two routinely leads the starters in hit %, but because they largely swap out playing time at middle blocker, never get a full set’s worth of action like Bergmann gets.

From our math, if Moss had as many attack chances per set as Bergmann, she’d have 5.94 k/s, a little more than Bergmann at 5.32. Breland Morrissette would have 11.08 k/s, DOUBLE what Bergmann hits per set. She currently has 27% as many attacks at Bergmann. Morrissette at a .416 hit % does not waste her chances when she gets them. She has 23 attack errors all season. Erin Moss is the next best of the starters at 48 (excluding D’Amico and Pimentel who rarely attack).

This begs the question, should Tech change their offensive approach to give Morrissette more chances if she’s scoring at a more efficient rate? Maybe. We are not experts in volleyball strategy, but we do know that part of why Breland’s efficiency is good is because it’s a sneak attack shot. She changes the tempo off of Bertolino/Bergmann/Otene to keep blockers guessing. Any noticeable shift in tactics to favor Breland would certainly invite a defensive response, but then does that leave Bergmann with even more freedom when she attacks? Either way Breland is one of the necessary elements that makes Tech’s team so well rounded.

This isn’t everything, but covers the main things we found that are most important to Tech has gotten to where it is, and where it could still find some improvement down the stretch.

Tech plays tonight against Miami at 7pm on ACCNX, followed by a visit to Tallahassee to play FSU on Sunday at 1pm.