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NCAA Men's College Basketball Tournament Trends - Part II

Updated: March 10, 2014

As I mentioned in Tournament Trends Analysis Part I, seeding is by far the most important factor in a team's tournament success, but I have made it my goal to find out which other factors determine who advances and who doesn't in the NCAA Tournament. In Part I, I analyzed seeding, a team's record in the last 10-12 games, record against the RPI Top 50, road/neutral record and experience.

In this analysis, I tested theories on tournament success based on each team's statistics, including field goal percentage, rebounding and turnovers. I used team statistical data from the years 1998 to 2013 to test my theories. I used the same criteria as I did Tournament Trends Analysis Part I. That is, I analyzed all games between teams where the seed differential was 3 or less, excluding matchups of a 1 seed vs a 4 seed. This gave me a total of 331 games to analyze where the team with the better seed was 169-150 (53%).

Disclaimer

Let me start by saying that this site does not support or encourage gambling. I have provided this information for the amusement of college basketball fans and stat junkies like myself. If this helps you fill out your brackets that's great, but I would never advise anyone to gamble with money that they cannot afford to lose. The beauty of the NCAA pool is that it is very low risk with a possible high reward and the tournament is much more interesting when you have someone to root for. The following information is based on trends in the tournament over the past 15 years. There is no guarantee that these trends will continue this season. More importantly, even if these trends do hold true, they give you only a slight edge. Most of what happens in the tourney is pure chance and it takes a lot of luck to do well in your NCAA pool. Please feel free to email me and let me know what you think about the results. However, if you complain to me because you used these trends and they did not help you choose winners, I will not listen. Use this information at your own risk.

Theory 1 - The better shooting team will win the majority of the time

My first theory was that good shooting teams (teams with high field goal percentages during the season) would have much more success in the tournament. The way that I see it, defensive intensity increases at tournament time so outside shots will be that much tougher to make. A good shooter (or in this case good shooting team) is much better equipped to overcome tight defensive pressure than a poor shooting team. Because it didn't make sense to compare situations where one team's shooting efficiency was only fractionally better than their opponent, I limited the analysis to situations where one team had an average field goal percentage at least two percentage points better than their tournament opponent. I found 162 such matchups between 1998 and 2013. My theory proved accurate as the team with the higher field goal percentage was 92-70 (56.8%). When I limited the analysis to matchups between teams with field goal percentages three ormore percentage points apart, the better shooting team was 52-43 (54.7%). So, teams that shoot better from the floor win more often. In the past two years, however, teams with the 2 percentage point (or more) advantage are 9-9.

Theory 2 - The team with the better field goal percentage defense will win the majority of the games

Again I started with the 2% rule. That is, I only analyzed games in which one team's average field goal percentage defense (in other words, their opponent's field goal percentage) was at least two percentage points better than the other team's field goal percentage defense. Unfortunately, this theory did not prove to be very strong. In 145 games, the team with the lower opposition field goal percentage was 75-70 (51.7%). In fact, the better defensive teams were 10-13 in the past two tournaments.

Theory 3 - Teams that consistently make their free throws will win more often than not

Anyone who has watched college basketball over the years has seen many games lost because one team was not able to make their free throws. The question is: does data from the NCAA Tournament support this? I felt like this would be one of the critical measures for judging who will win games between evenly matched teams. I rarely pick a poor free throw shooting team to beat a similarly-seeded team that shoots a solid percentage from the charity stripe. Obviously, the close games are much more likely to be decided at the free throw line. This time, I limited my data set to matchups between teams with free throw percentages at least 4 percentage points apart. I came up with 126 occurrences and the team with the better free throw percentage was 65-61 (51.6%). These results were disappointing.

Given that free throw shooting has a bigger impact in close games, I also looked at games where the final margin of victory was 6 points or less and the free throw shooting gap between the teams was at least 4 percentage points. These were 53 such games with the better free throw shooting team going 26-27.

Theory 4 - The better rebounding teams will have more success in the Tournament

My theory is that teams will be playing much better defense in the tournament and therefore more shots will be missed. Given more missed shots, there will be more rebounds. With more available rebounds, the better rebounding teams will be at much more of an advantage. At least that is how I see it. I started analyzing this data by calculating a defensive rebounding percentage and an offensive rebounding percentage. A team's defensive rebounding percentage is their average defensive rebounds divided by the sum of their average defensive rebounds and their opponent's average offensive rebounds. In other words, the percentage of available rebounds that the team was able to collect on the defensive end. Offensive rebounding percentage was calculated similarly.

DEFENSIVE REBOUNDING PERCENTAGE =
DEFENSIVE REBOUNDS / (DEFENSIVE REBOUNDS + OPPONENTS OFFENSIVE REBOUNDS)

OFFENSIVE REBOUNDING PERCENTAGE =
OFFENSIVE REBOUNDS / (OFFENSIVE REBOUNDS + OPPONENTS DEFENSIVE REBOUNDS)

I chose this method rather than actual total rebounds because total rebounds is more a function of shooting percentage. In other words, a team that holds its opponents to a very low shooting percentage will grab more defensive rebounds, but this does not make them a good defensive rebounding team. To test this theory, I applied a 4% differential rule (at least 4 percentage points difference in rebounding percentage between the two teams). In those games, the team with the better defensive rebounding percentage was 54-40 (57.4%), but only 5-7 in the past two years. Using the same analysis for offensive rebounding prowess, I found that the better offensive rebounding team was 53-60 (46.9%). I am surprised by these differences. I would think that the ability to reduce second chances on the defensive end would be no less important than getting those second chances on the offensive end. But these results indicate that protecting your own glass is more critical to NCAA Tournament success.

Theory 5 - The team with the better turnover margin will win the majority of games

Turnover margin is defined as the difference between a team's average number of opponent turnovers forced and the average number of turnovers committed. A positive number indicates that a team takes better care of the ball than their opponent which is critical during tournament time, especially given that single-elimination stress and tighter defense will result in an increased number of turnovers. I started by simply looking at all games where one team's average turnover margin was better than their opponent's average, regardless of whether both were positive or negative. I found that the team with the better turnover margin (minimum difference in turnover margin of 2.0 turnovers per game) was 87-81 (51.8%). The data suggests that turnover margin has a minimal impact. I think this reflects the difference between tournament play and the regular season. I haven't seen statistics to back this up, but I'm guessing that teams commit more turnovers, on average, in the NCAA Tournament than they do in the final month of the regular season. The pressure of tournament play, higher defensive intensity and better overall competition makes taking care of the basketball more difficult.

Conclusions

Based on the data, the strongest statistical factors affecting who will win NCAA Tournament games between similarly seeded teams are field goal percentage and defensive rebounding prowess. Still, the advantages are relatively slight. As I have mentioned before, knowing your seeds and good old fashioned luck is required to win a large NCAA Tournament pool. The statistics above must also be taken with caution because not all conferences are created equal. For example, a team with a 45% team field goal percentage that plays in a defensive-minded conference is probably a better shooting team than a school that averages 47% from the field in a mediocre defensive conference. I think some important knowledge can be gleaned from these statistics, but conference affiliation must be considered when examining these statistics.

Statistic Record Win Pct
Team with Higher FG% (minimum 2% better) 92-70 57%
Team with Lower Opponent FG% (minimum 2% better) 75-70 52%
Team with Higher FT% (minimum 4% better) 65-61 52%
Team with Better Defensive Rebounding Pct (min 4% better) 54-40 57%
Team with Better Offensive Rebounding Pct (min 4% better) 53-60 47%
Team with Better Turnover Margin (minimum diff of 2) 87-81 52%

If you would like to take a look at these team stats in greater depth, I suggest visiting the college basketball page at StatFox.com.

Other Analysis

Please take a look at my March Madness Analysis Part I page. There you will find analysis based on a variety of team variables including:






NCAA Tournament Links
NCAA Trends Part I
NCAA Upset Trends
ESPN College Hoops
CBS Sports College Hoops
StatFox.com
StatSheet.com

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