My favorite aspect of win probability models is the concept of leverage. As Ken Pomeroy wrote in 2010, Leverage measures how much is at stake on a particular possession. 
 
I’m especially interested in how leverage functions as an unorthodox stand-in for excitement level and game tension in basketball. 

Considering we now have win probability graphs for five years’ worth of NCAA tournaments, I thought it would be fun to examine which of the tourney games played over the past half-decade contained the largest percentage of high-impact possessions— and thus had the most high-leverage basketball. The sample spans 332 NCAA tournament games played from 2010-2014. Before we review the games, here is more from Ken’s introduction to leverage: 

The colors [denoting leverage] range from blue, where win probability is largely unaffected by the potential outcome of a possession, to yellow, where the outcome of a possession can have significant impact on the win probability (more precisely, at least a 10% swing between a 2-point possession and zero points). Leverage is not based on what happened during the possession, but is the range of win probability based on what could have happened.

And here is a relevant excerpt from a piece I did on leverage last year: 

By categorizing possessions within a game by leverage, we can distill the substance of a close game to its most granular level: the range of outcomes of a single possession. It is on these graphs that we are able to see which possessions were most important, even if they did not seem so at the time. 10+ percent swings in win probability are momentous and exciting to think about, especially when they’re happening at various, seemingly tranquil points in the game.

Below are the 15 NCAA tournament games (played from 2010-2014) with the largest percentage of high-impact possessions, listed in order from lowest to highest. If you have a subscription, be sure to also click on the win probability graphs for each game listed. It’s half the fun and they feature a lot of yellow.
 
15. (7) Connecticut 89, (10) Saint Joseph’s 81 (OT), 3/20/14, Second Round, East Regional
Win probability to start game: Connecticut (63.5%)
Percentage of high-leverage game time: 66.9% (1,805 high-leverage seconds out of 2,700 total)
Longest string of high-leverage possessions: 1:07 remaining in first half (St. Joe’s up 39-32) until 2:12 remaining in overtime (UConn up 77-73)

Comments: From late in the first half until more than halfway through overtime, every game possession was played at high leverage, meaning that for every possession played during that time there was the possibility of at least a 10 percent swing in win probability between a 2-point possession and a zero-point one. According to the model, the Hawks had an 89 percent chance of winning after two Chris Wilson free throws put them up 70-67 with 49 seconds remaining. Amida Brimah converted a three-point play to tie it at 70 and the teams missed a basket each before the game went to overtime. According to WP, the game finally left the high-leverage zone when Shabazz Napier converted a three-point play to put the Huskies up 80-73 with 1:20 to go in the extra period. (PBP, WP graph

14. (4) Michigan State 61, (1) Virginia 59, 3/28/14, Sweet 16, East Regional
Win probability to start game: Virginia (62.5%)
Percentage of high-leverage game time: 67.1% (1,610 high-leverage seconds out of 2,400 total)
Longest string of high-leverage possessions: 6:22 remaining in first half (Michigan State up 23-17) until 5:26 remaining (Michigan State up 51-44)

Comments: This game played at Madison Square Garden is the first of several on the list featuring Michigan State. Win probability was about 50/50 when Virginia’s Justin Anderson hit a three-pointer to tie the game at 51 with 1:49 left. An Adreian Payne triple on the next possession gave the Spartans a lead they wouldn’t relinquish, although the Cavaliers got to within two with ten seconds left and within one with two seconds left. Nearly the entire second half was played at high leverage, save for the possession after the Spartans went up 51-44 at the 5:26 mark. (PBP, WP graph

13. (5) Michigan State 59, (9) Northern Iowa 52, 3/26/10, Sweet 16, Midwest Regional
Win probability to start game: Northern Iowa (50.4%)
Percentage of high-leverage game time: 67.6% (1,623 high-leverage seconds out of 2,400 total)
Longest string of high-leverage possessions: 19:33 remaining in game (Northern Iowa up 29-24) until 0:59 left in second half (Michigan State up 55-51 with the ball)

Comments: The game started as a toss-up and was played like one throughout. Like many games on this list, nearly every second-half possession was played at high-leverage. Northern Iowa stood at roughly 60% win probability up 46-44 with 7:47 to go. The game left high-leverage mode when the Spartans were up 55-51 with the ball under a minute remaining. (PBP, WP graph
 
12. (3) Marquette 74, (6) Butler 72, 3/23/13, Third Round, East Regional
Win probability to start game: Marquette (58.2%)
Percentage of high-leverage game time: 67.7% (1,625 high-leverage seconds out of 2,400 total)
Longest string of high-leverage possessions: Halftime (Butler leading 35-29) until 0:22 left in game (Marquette leading 72-69)

Comments: This is the first of Butler’s multiple appearances on this list. The entire second half was played at high leverage. Down 72-70 with five seconds left, Butler’s Rotnei Clarke missed a possible game-winning three pointer, allowing the Golden Eagles to advance to the second weekend.
(PBP, WP graph

11. (10) Georgia Tech 64, (7) Oklahoma State 59, 3/19/10, First Round, Midwest Regional
Win probability to start game: Georgia Tech (52.9%)
Percentage of high-leverage game time: 68.6% (1,647 high-leverage seconds out of 2,400 total)
Longest string of high-leverage possessions: 3:13 left in first half (Georgia Tech up 34-27) until 0:17 left in game (GT up 64-59).

Comments: The 2010 Midwest Regional, like all NCAA tournament regionals, consisted of 15 games. A mind-boggling four of those made this final list! This game featured over 20 basketball minutes of unbroken high-leverage, which did not let up until two Maurice Miller free throws put the Yellow Jackets ahead 64-59 with 17 seconds left in the contest. (PBP, WP Graph

10. (9) Northern Iowa 69, (8) UNLV 66, 3/18/10, First Round, Midwest Regional
Win probability to start game: Northern Iowa (60.1%)
Percentage of high-leverage game time: 68.7% (1,649 high-leverage seconds out of 2,400 total)
Longest string of high-leverage possessions: 4:38 first half mark (29-29) until 7:45 left in second half (Northern Iowa up 55-49)

Comments: Here’s another one from that crazy 2010 Midwest Regional. The game left the high-leverage zone a bit early when Adam Koch converted a three-point play to put the Panthers up 58-49 with 7:22 to go. But the Runnin’ Rebels clawed back and tied it at 66 with 40 seconds left. Ali Farokhmanesh’s three-pointer with eight seconds remaining clinched the opening round victory for UNI and were the last points of the game.
(PBP, WP Graph

9. (5) Michigan State 70, (6) Tennessee 69, 3/28/10, Elite Eight, Midwest Regional
Win probability to start game: Michigan State (52.9%)
Percentage of high-leverage game time: 68.8% (1,650 high-leverage seconds out of 2,400 total)
Longest string of high-leverage possessions: 6:42 left in first half (Tennessee up 32-29) until end of game.

Comments: The final appearance from the 2010 Midwest Regional was also the most thrilling by win probability leverage standards. The game ended with 26 consecutive minutes of high-leverage possessions. Raymar Morgan made the decisive free throw for MSU with two seconds left to lift the Spartans to the Final Four. (PBP, WP Graph

8. (8) Butler 71, (1) Pittsburgh 70, 3/19/11, Third Round, Southeast Regional
Win probability to start game: Pittsburgh (71.7%)
Percentage of high-leverage game time: 69.3% (1,664 high-leverage seconds out of 2,400 total)
Longest string of high-leverage possessions: 5:21 remaining in first half (Butler up 30-20) until 10:37 left in second half (Pittsburgh up 53-48)

Comments: The game is remembered in part for a wild ending in which the teams exchanged ill-advised fouls in the last two seconds of the contest. The Bulldogs’ Matt Howard sank a free throw with one second left for the final point of the game. The game briefly left the high-leverage zone when the Panthers took a 53-48 lead halfway through the second half. Free throws by Butler’s Andrew Smith made it 53-50 shortly thereafter, however, and sent the game back squarely into high-leverage possessions that did not let up until the buzzer sounded.  (PBP, WP Graph

7. (13) Murray State 66, (4) Vanderbilt 65, 3/18/10, First Round, West Regional
Win probability to start game: Vanderbilt (52.1%)
Percentage of high-leverage game time: 69.4% (1,665 high-leverage seconds out of 2,400 total)
Longest string of high-leverage possessions: 6:46 mark in first half (Vanderbilt leads 27-26) until end of game

Comments: Like the Tennessee/Michigan State thriller ten days later, this game ended with just under 27 straight minutes of high-leverage basketball. The contest was back and forth for much of the game’s final five minutes and a Danero Thomas jumper at the buzzer sent the Racers on to the second round. (PBP, WP Graph

6. (10) Stanford 60, (2) Kansas 57, 3/23/14, Third Round, South Regional
Win probability to start game: Kansas (68.6%)
Percentage of high-leverage game time: 70.8% (1,699 high-leverage seconds out of 2,400 total)
Longest string of high-leverage possessions: 18:36 left in first half (Kansas up 28-26) until 0:32 left in game (Stanford up 56-51)

Comments: This is the first game on the list to have had more than 70% of the game played at high-leverage. Kansas sat at 80 percent win probability after a Tarik Black bucket put the Jayhawks ahead 28-23 with 18:49 to go. Stefan Nastic’s three-point play on the ensuing possession sent the game back into high-leverage mode, where it remained until the Cardinal went up five with under a minute left. (PBP, WP Graph

5. (8) Butler 60, (9) Old Dominion 58, 3/17/11, Second Round, Southeast Regional
Win probability to start game: Butler (50.8%)
Percentage of high-leverage game time: 71.9% (1,725 high-leverage seconds out of 2,400 total)
Longest string of high-leverage possessions: 7:29 remaining in first half (Old Dominion up 21-19) until end of game

Comments: Both of Butler’s 2011 NCAA tournament games played at D.C.’s Verizon Center came down to the final possession. In this contest—like the one against Pittsburgh—Matt Howard scored the decisive bucket, a tip-in at the buzzer. The game ended with 27 consecutive minutes of high-leverage basketball. (PBP, WP Graph

4. (5) Butler 52, (5) Michigan State 50, 4/3/10, Final Four
Win probability to start game: Butler (60.0%)
Percentage of high-leverage game time: 72.2% (1,733 high-leverage seconds out of 2,400 total)
Longest string of high-leverage possessions: 8:11 left in first half (Michigan State up 22-17) until end of game.

Comments: It’s fitting the two teams with the largest amount of NCAA tournament high-leverage basketball over the past five years met in the 2010 Final Four, making this game’s possessions possibly the most high-impact during that span. The game ended with 28 minutes of high-leverage possessions. Though the entire second-half was a nail-biter, Butler never trailed after taking a 34-33 lead on a Shelvin Mack jumper with 17:42 to play. The Bulldogs intentionally fouled Korie Lucious with two-seconds left up 52-49 and sealed it when he made one of two free throws. It would be the first of two-consecutive championship game appearances for Butler.  (PBP, WP Graph

3. (13) La Salle 76, (12) Mississippi 74, 3/24/13, Third Round, West Regional
Win probability to start game: Mississippi (60.0%)
Percentage of high-leverage game time: 72.5% (1,739 high-leverage seconds out of 2,400 total)
Longest string of high-leverage possessions: 8:16 left in first half (La Salle up 25-20) until end of game

Comments: This wild game featured the span’s longest string of unbroken high-leverage basketball—ending on over 28 minutes of high-leverage possessions. Mississippi’s win probability reached as high as 85 percent after a Reginald Buckner layup made it 69-64 with 4:18 to go. Tyrone Garland’s basket—dubbed a “Southwest Philly Floater”— with two seconds left sent the Explorers to the Sweet 16. (PBP, WP Graph

2. (11) VCU 72, (10) Florida State 71 (OT), 3/25/11, Sweet Sixteen, Southwest Regional
Win probability to start game: Florida State (54.7%)
Percentage of high-leverage game time: 73.5% (1,984 high-leverage seconds out of 2,700 total)
Longest string of high-leverage possessions: 7:17 remaining in first half (VCU up 22-21) until 7:55 left in regulation (VCU up 61-53)

Comments: This contest featured the most high-leverage minutes of any game during the past five NCAA tournaments, notching over 33 basketball minutes at high-leverage. VCU’s win probability cleared 90 percent when Rob Brandenburg’s steal gave VCU the ball up 62-53 with 7:13 to go. The game returned to the high-leverage zone after a Michael Snaer three made it 62-56 on FSU’s next possession. The teams played a riveting overtime and Bradford Burgess’s layup with under ten seconds to go in OT earned the Rams a trip to the Elite Eight.  (PBP, WP Graph

1. (2) Kansas 63, (10) Purdue 60, 3/18/12, Third Round, Midwest Regional
Win probability to start game: Kansas (73.6%)
Percentage of high-leverage game time: 75.0% (1,800 high-leverage seconds out of 2,400 total)
Longest string of high-leverage possessions: 7:06 left in first half (Purdue up 23-19) until end of game

Comments: The only game from the 2012 tournament on the list is also the crown jewel of high leverage basketball. 30 of the game’s 40 minutes were played at high-leverage. Purdue jumped out to an early lead and didn’t trail until an Elijah Johnson three-pointer put the Jayhawks up 57-56 with 3:04 left in the game. Still, the Boilermakers stood at 81 percent win probability after rebounding a Thomas Robinson miss leading 60-57 with 1:44 to play. KU scored on their next three possessions— and held the Boilermakers scoreless on their last three—to advance to the Sweet 16 en route to the title game.
(PBP, WP Graph)