Women's College Liberos: Part I (Serve Receipt)

Over at the VolleyTalk discussion boards, there has been periodic debate as to who the top liberos (backcourt defensive specialists) are in the women's college game. Two measures -- serve-receipt and digs -- seem particularly relevant to judging the merits of different liberos. I will look at serve-receipt in the present posting and then examine digs in Part II. Three players I will focus on, in particular, are USC's Natalie Hagglund, Iowa State's Kristen Hahn, and Michigan State's Kori Moster.

For studying these matters, the ideal would be to have observer ratings of the quality of each pass and dig made by a player, such as many teams compile from their study of game video. Lacking such ratings, we can only look at box scores published online. For serve-receipt, moreover, one really needs to find extended or detailed box scores to get good information (here's an example of both a regular and detailed box score being available).

Regular box scores contain each player's serve-reception errors (RE), but not player-specific information on number of serve-receipt opportunities. For the latter, one needs a detailed box score. A confusing aspect of detailed box scores is that, for some matches, a column in the serve-reception section with "O" at the top presents each player's total number of opportunities, whereas for other matches, the "O" column contains each player's number of successful receipts, which need to be added to reception errors to arrive at reception opportunities. The meaning of "O" for any given match can be determined by looking at the opposing team's number of non-error serves.

What formulas can be devised to combine serve-receipt data into a measure of skill at the task? Certainly, receiving a lot serves without error is an important quality. Also, arguably, receiving a large share of the serves directed to one's team is a marker of receipt skill. Someone who receives, say, 40 percent of balls served to her team probably has a wider range of movement and is willing to take more initiative than someone else who receives, say, 10 percent of serves. If a player can receive a lot of balls and do so with very few errors, that's probably someone you want on your team. (Ideally, that player would exhibit not only non-error passing, but also high-quality passing that lets the team's offensive attack run "in system." However, quality ratings are not available online.*)

My first idea for a formula to measure serve-receipt prowess would multiply, for a given match, a player's success rate at receiving serve (non-error receipts over total receipt opportunities) by the proportion of a team's serve receipts the focal player took (total number of serve-receipts is equal to the opponent's number of non-error serves). So, for example, if a player successfully executes .90 of her serve-receipts and takes .30 of her team's receipts, that would yield a score of .27.

The more I thought about it, however, I felt greater weight should be given to punishing serve-receipt errors. To do so, I simply converted the first part of the formula to receipt-success-rate squared. If a player makes no reception errors, her success rate of 1.000 remains the same when squared. A player with a low error rate (e.g., success rate of .90) is punished mildly, as the success-rate squared becomes .81. A serve-receiver who is mediocre at best (e.g., success rate of .60) suffers more heavily under squaring, as her value plummets to .36. Thus, my current working formula is as follows (^2 stands for squared):

(non-error receipts over total receipt opportunities)^2   X   (proportion of team's serve receipts player took)

Although detailed box scores do not seem to be widely available, Hagglund's school, USC, nearly always provides them. I examined all of SC's Pac-12 conference matches this season, except for the Trojans' loss to Arizona last weekend (for which I couldn't find a detailed box score). Hagglund very rarely botches a serve-receipt, doing so only twice in the seven matches (and 70 reception opportunities) summarized in the following table.

Natalie Hagglund

Opponent	Serve Receipt (Success-Error-Total)	% Success  (S)	% of Team's Receipts (R)	(S^2)R
UCLA	11-0-11	1.000	.136 (11/81)	.136
Utah	10-1-11	.909	.220 (11/50)	.182
Stanford	8-0-8	1.000	.136 (8/59)	.136
Cal	23-0-23	1.000	.237 (23/97)	.237
Oregon St.	3-0-3	1.000	.086 (3/35)	.086
Oregon	7-0-7	1.000	.113 (7/62)	.113
Arizona St.	6-1-7	.857	.149 (7/47)	.109

Average of values in final column = .143

However, Hagglund doesn't receive a lot of serves, either, usually between .10-.15 of opponents' launches. Her greatest serve-receipt activity occurred in a five-game win over Cal, in which Hagglund flawlessly passed along 23 of the Golden Bears' 97 non-error serves (.237). Even though the squaring of serve-receipt success rates helps Hagglund (because her success rate is usually 1.000, which is undiminished by squaring), her final scores are not that high, due to her low share of Trojan serve-receipts. (SC outside hitters Sara Shaw and Samantha Bricio regularly field more opposing serves than does Hagglund.) Averaging Hagglund's final scores for the seven matches, she ends up with a value of .143, which is much lower than those for other players we'll review.

Next up is Kristen Hahn. Because of the dearth of this year's Big 12 conference matches for which I could find detailed box scores, I dipped back into the 2012 NCAA tournament (to ensure high quality of opposition). Hahn appears more error-prone than Hagglund, compiling six blown receipts in the five matches examined. However, Hahn is much more active on serve-receipt than Hagglund, a trend that has intensified with Cyclone outside hitter (and frequent serve-receiver) Rachel Hockaday finishing her college career last season.

Kristen Hahn (Iowa State)

Opponent	Serve Receipt (Success-Error-Total)	% Success (S)	% of Team's Receipts (R)	(S^2)R
IPFW*	13-3-16	.812	.222 (16/72)	.146
N Carolina*	27-0-27	1.000	.284 (27/95)	.284
Stanford*	26-2-28	.929	.394 (28/71)	.340
Baylor	16-0-16	1.000	.364 (16/44)	.364
Kansas	47-1-48	.979	.490 (48/98)	.470

Average of values in final column = .321
*2012 NCAA Tournament

Hahn's most recent performance, in Iowa State's five-game win Wednesday night at Kansas, was quite remarkable. She received nearly half of the Jayhawks' serves (48 of 98) and made only one error in the 48 attempted receipts. Hahn compiled a .470 score in the Kansas match and averaged a .321 for the five matches of hers that were studied.

Hahn recently told the Iowa State Daily that, "I think serve receive is a very mental game. I think just making sure that mentally, I’m ready to go... I like to observe their servers during warm-ups and know who the starting servers are and what their go-to zone is and what they practice."

Our third contender is Michigan State's Kori Moster, who Spartan coach Cathy George discussed on the October 21 edition of the Internet radio volleyball show, The Net Live.

Kori Moster (Michigan State)

Opponent	Serve Receipt (Success-Error-Total)	% Success (S)	% of Team's Receipts (R)	(S^2)R
Ohio St.	30-0-30	1.000	.484 (30/62)	.484
Illinois	12-0-12	1.000	.273 (12/44)	.273
Minnesota	28-5-33	.848	.308 (33/107)	.221
Wisconsin	15-0-15	1.000	.176 (15/85)	.176

Average of values in final column = .288

Again focusing on this year's conference matches, I found only four of Moster's Big 10 matches that had detailed box scores. In three of these, Moster received serve impeccably. However, Moster made five serve-reception errors October 17 vs. Minnesota, an unusually high number for a potentially elite libero. In that match, the Gophers' Daly Santana served seven aces, at least some of which were at Moster's expense. For the quartet of matches studied for Moster, she averaged a score of .288, slightly below Hahn's.

One other libero I wanted to mention is Rachel Brummitt of Texas Tech (where I'm on the faculty). During 2012, Brummitt twice won Big 12 Defensive Player of the Week (to Hahn's eight times). I was only able to find a detailed box score for one of the Red Raiders' matches this season, against Kansas. In that match, Brummitt successfully received all 11 serves she faced, but these 11 made up a small proportion of non-error Jayhawk serves (11/73 = .151).

If anyone has additional liberos to suggest, please let us know in the Comments section to this blog. Remember, the current entry was only on serve-receipt. Liberos' digging statistics will be examined in a future posting.

---

*As I later learned from VolleyTalk, the FIVB's serve-receipt statistics for international play include a count of how many receipts were "excellent."

Torrid Toreros Take Season by Storm

The break-out team of the women's college season thus far is the University of San Diego, which has risen to No. 2 in the national rankings. The Toreros, featured in this article from ESPN-W's Mechelle Voepel, have played a very tough non-conference schedule and lost only once -- in five games to defending NCAA champion Texas. Last Friday's win over USC really put the Toreros on the national map. West Coast Conference play begins for USD tomorrow night, as the Toreros play at BYU in a match-up of last year's WCC co-champions (the match will be shown on BYU TV, which some cable/satellite systems carry).

Longtime readers of this blog know that I consider hitting percentage the key volleyball statistic. That was the first thing I looked at for USD and indeed the Toreros have shined on this metric. I have plotted the match-by-match hitting percentages for five USD players who get the bulk of the team's spike attempts and for the team as a whole, in the following graph (you can click on the graph to enlarge it).

So far, the Toreros have been riding the arms of senior middle-hitters Chloe Ferrari and Katie Hoekman. Ferrari, who missed the last month of the 2012 season due to ACL injury, has consistently hit at or around the .400 level so far this season, except for the UC Santa Barbara match, in which she hit a perfect 1.000 (6 kills in 6 attempts). Hoekman had a big match in the opener against Texas-El Paso, hitting .708, with 18 kills and only 1 error in 24 attempts. She has hit nearly as high as Ferrari in most of USD's matches. Alaysia Brown, listed as both a middle and outside hitter, is a barometer of how the team as a whole is doing offensively, in the sense that her match-by-match hitting percentages (depicted in the bright blue small dashed line) tracks closely with the team's overall hitting percentage (the heavy bright blue line).

It hasn't only been offense that's taken the Toreros to where they are. They've shut down prominent opposing hitters such as Texas's Haley Eckerman (-.095 hitting percentage), Iowa State's Victoria Hurtt (.071), and USC's Samantha Bricio (.068).

Against 'SC, digging played a big role in the Toreros' four-game victory. USD retrieved 56% of the Trojans' non-error spike attempts (81 digs of 145 'SC hits that were either kills or kept in play). The Trojans' rate of digging USD's non-error spike attempts was only 37%. The Toreros' big digging advantage offset a large USC edge in total team blocks (15-4).

Nike Big Four Tournament in Austin

Four of the nation's top collegiate women's volleyball teams gathered in Austin, Texas this past weekend and it was the host University of Texas Longhorns compiling the best record of the teams, 2-0. All of the match-ups were prearranged, rather than a format of semi-finals and finals being used. UT's wins were both close: 25-27, 25-17, 13-25, 25-21, 15-10 over Penn State, and 29-27, 18-25, 25-16, 27-25 over Stanford. Box scores of the four matches are available at the following links: Texas-Penn State, Texas-Stanford, Florida-Stanford, and Florida-Penn State.

My initial interest was in looking at which players hit at a consistently high level over their teams' two matches. I created the following chart (on which you can click to enlarge), focusing on players who took 20 or more hitting attempts in a match. Highlighted in blue are players who hit (roughly) .300 or better in both of their matches.

Four middle-blockers hit well in both of their matches: Penn State's Katie Slay, Florida's Chloe Mann, and Stanford's Inky Ajanaku and Carly Wopat. Cardinal outside-hitter Brittany Howard recorded attack percentages of .290 and .300 against Florida and Texas, respectively.

Oddly, the team that compiled the best record, Texas, had no players who hit for a high percentage in both matches, and the team with the worst record, Stanford, had three such players. I therefore decided to probe Stanford's matches a little more closely, as shown in the next chart.

Stanford was outplayed by Florida across the statistical indicators examined, although not by a lot. The Gators' winning score of 28-26, 25-17, 18-25, 25-22 thus seems consistent with how the teams played. The Texas-Stanford match was a different story. Stanford statistically outperformed UT in three categories -- hitting, blocking, and digging -- yet still lost in four. The "Cardinal sin" occurred in the serving game. Stanford botched 16 serves against Texas, while scoring only three aces. The Longhorns, in contrast, had much more balanced numbers of aces (9) and errors (11).

Texas also benefited from errant opposition serving vs. Penn State, as the Nittany Lions amassed 22 service errors (with six aces). It may be a case where the Longhorns' reputation precedes them; out of respect or fear of the UT offensive attack, opposing teams may feel it necessary to serve extremely aggressively.

Hawai'i Tops Texas on 2013 Opening Night

Defending NCAA champion and preseason No. 1 Texas had neither an answer for host Hawai'i's offensive prowess nor much of an attack itself (except for Game 2), as the Rainbow Wahine prevailed in four games, 25-19, 19-25, 27-25, 25-16 (box score).

Youth was served for Hawai'i, as frosh OH Nikki Taylor (10-1-18) and soph MB Jade Vorster (7-0-14) each hit .500 for the match, committing only one hitting error between them. Junior middle Kalei Adolpho added a .421 night for the 'Bows (11-3-19). The following graph shows each team's hitting percentage per game, with the winning team in each game listed at the bottom. You can click on the graphic to enlarge it.

Frosh OH Pilar Victoria (10-3-23, .304) was a rare bright spot for the Longhorns.

In Friday night's other marquee match (in my view), USC defeated host Purdue in four.

Opening of 2013 Women's College Season

The 2013 women's college season gets underway today. ESPN "W" (for women's sports) writer Mechelle Voepel has a pair of articles (here and here) previewing the season, so I'll just add some brief remarks at this point. I've put together the following chart, showing the preseason polls for three major outlets: the American Volleyball Coaches Association, ESPN W, and Volleyball Magazine (you can click on each column heading to be taken to the full reports on the preseason polls). The polls are identical in their top three. Further, the same 10 schools appear in all three polls' Top 10.

	AVCA	ESPN W	VB Mag
1	Texas	Texas	Texas
2	Penn St.	Penn St.	Penn St.
3	Stanford	Stanford	Stanford
4	USC	Minnesota	USC
5	Washington	USC	Minnesota
6	Minnesota	Florida	Washington
7	Michigan	Oregon	Michigan
8	Oregon	Michigan	Nebraska
9	Florida	Washington	Oregon
10	Nebraska	Nebraska	Florida

Defending NCAA champion Texas, which returns front-court stars Haley Eckerman (outside), Bailey Webster (outside), and Khat Bell (middle), is the consensus preseason No. 1. The Longhorns' main loss from last year is versatile Sha'Dare McNeal, who hit .364 and recorded 2.41 digs per game as a senior last year, both second-highest on the team (on hitting percentage, I'm excluding a player with only 25 attempts all season). In addition, McNeal's 0.85 blocks per game were third on the squad. Texas opens up the season tonight at Hawai'i, in a match that starts after midnight for those of you in the Eastern and Central time zones.

Another interesting opening-night match features USC at Purdue. The Trojans return nearly all of their top players from a year ago, led by OH Samantha Bricio. The same can't be said for the Boilermakers, with Ariel Turner having moved on. Turner alone took 37% of Purdue's hitting attempts  a season ago (1622/4347); further, no other Boilermaker was within 1,000 spike attempts of Turner.

40 Years of Following Volleyball

The summer of 2013 marks my 40th year of following volleyball. The following photo montage shows me in Israel in 1973, as I traveled with my father, a USA team organizer, to the Maccabiah Games, an international competition for Jewish athletes. Among the players pictured in action is Ed Becker, a  former UCLA star who was once mentioned in Sports Illustrated (in the middle, going from left to right, of the five USA players shown).

Further information on my volleyball background is available here. With next week's start to the NCAA women's season, I look forward to my 41st year of following the sport and my seventh year of analyzing and writing for this blog.

Guest Contributor Adam White Suggests New Statistic: "Gift" Points to the Opponent

Adam White is a graduate student at Bowling Green State University. Here is his idea:

I call the statistic “gifts.” Like any worthy measure, gifts are simple to understand and to calculate, yet aspire to novel explanatory force.

Gifts are the difference between a team’s total points scored and the points they scored on kills. This reflects the number of non-kill or “unearned” points handed to them by the other team.

For example, say [Texas Tech] beats BGSU 25-21, but the Falcons outhit the Red Raiders 15-14. This entails that BGSU gave TTU 11 gifts (25-14), while TTU gave BGSU only 6 gifts (21-15).

The point is that, in this case at least, the gifts explain the TTU victory better than do the kills. (This is an exception, but not a rarity.)

“Gifts per set” is probably the best way to track and analyze the measure. Teams would have both a “gifts received” and a “gifts given” figure.

Arguably "gifts given" measures the consistency and effectiveness of a team’s all-around ball handling. A team with a high "gift received" average is likely capable of longer rallies.

These assumptions have been supported by my modest research, as the BGSU varsity team has better gift statistics than does the group of very mediocre sandlot players I measured.