The Pi-Rate Ratings

February 20, 2020

Comparison of Old & New R+T Ratings

We hope you read our piece earlier this week describing our updated R+T Rating for 2020.  If you didn’t, and if you are a new reader to the PiRate Ratings, after thanking you for stopping buy and remembering you are getting exactly what you paid for here, the following is a quick tutorial on what R+T Rating means.

  1. The R+T Rating is a metric that applies only to the NCAA Tournament.

  2. The R+T Rating attempts to estimate extra scoring opportunities by teams in NCAA Tournament games.

  3. Over the last two decades when the needed statistics to calculate R+T Ratings, the National Champions and most of the Final Four teams rated near the top of the field in R+T Rating.  

  4. The reason the R+T Rating is so important in the NCAA Tournament only is because the other metrics are better applied in an environment where half of the teams in Division 1 are below average offensively, while a separate half of the teams in Division 1 are below average defensively.  In the NCAA Tournament, almost all teams are above average offensively and defensively, so these extra scoring opportunities frequently are the difference.   It only takes one nice scoring spurt to win a tightly contested game in the Big Dance.

We used the same R+T Rating for almost two decades, only slightly tweaking the weighting for these stats.  The old R+T Rating, which we will continue to publish this year, is:

(R * 2) + (S * .5) + (6 – Opp S) + T

R = Rebounding Margin
S = Average Steals Per Game
T = Turnover Margin

This metric shows that rebounding margin is more important than turnover margin, but steals are more important than other types of turnovers.  The reason is that steals lead to the most potential points per possession.  When a team steals the ball, they are usually facing their own basket (whereas on a rebound, their backs are to their own basket).  The team committing the turnover by steal must do a 180° turn to defend, and the stealing team takes off on a fast break.

This R+T Rating helped us pick some big upsets for many years.  Teams with high R+T Ratings and adequate strengths of schedule advanced in the tournaments at the expense of teams with low R+T Ratings.  In multiple years, teams with negative R+T Ratings lost quickly in the Big Dance, even teams that were #2, 3, and 4 seeds.  We correctly picked two different Georgetown teams to be upset as heavy favorites, because those Hoya teams had negative or very low positive R+T Ratings.  For three years, we picked Vanderbilt to lose in the first game against underdogs because Vanderbilt also had negative or very low R+T Ratings.  At the other end of the spectrum, the team with the highest R+T Rating and a significantly strong schedule has cut down the nets multiple times.

If the R+T Rating has been an accurate predictor of potential NCAA Tournament success, why did we need to create a new version?  We did so, because the old version simply counted actual margins without concerning itself with possessions.  Rate stats are more accurate than counting stats.  As we have used as an example many times, a team that outrebounds its opponents 35-30 has done a better job than a team that outrebounded its opponents 43-37.  Strictly counting 43-37 is +6 and 35-30 is only +5, but 35-30 is 53.85% while 43-37 is 53.75%, so 35-30 is a tad better.  We want our stats to be as accurate as possible, so we switched to rate stats over counting stats.

But, we have an issue.  The variables now must change as well, because percentages are totally different from standard numbers.  We have tried to back-test the new variables and include a constant to try to make the outcome look the same but more accurate.

Here is the explanation for the new R+T Rating.

1. Use 4-Factors Rate Stats
A. Offensive Rebound %
B. Opponents’ Offensive Rebound %
C. Steal %
D. Opponents’ Steal %
E. Turnover %
F. Opponents’ Turnover %

2. Take the difference in each stat from the national average for each stat. There will be discrepancies in the offensive and defensive averages due to D1 vs. D2 games, so we set the national average from the mean of the offensive and defensive norms.
For example: O Reb% = 28.43 & D Reb% = 27.79, then the mean Reb% for Division 1 in 2020 is 28.1.

3. For Rebounding Rate Margin & Turnover Rate Margin take the sum of offensive and defensive rates and divide by 2.
Example: A team’s OReb Margin is +6.4% and DReb Margin is -1.2%. Reb Rate Margin would be +2.6%

4. We Keep Steal Rate Margins Separate as in original R+T.

5. The New Formula Now Becomes:

((R*8)+(S*2+((5-Opp S)*2)+(T*4)))/2.75

 

Here’s how we calculate a sample new R+T Rate.

The Big State University Pumas have these stats

Offensive Rebounding % = 34.8.  With a national Rebound % mean of 28.1, Big State’s offensive rebound rate margin is +6.7% (34.8-28.1)

Opponents’ Offensive Rebounding % = 28.6.  With a national Rebound % mean of 28.1, The defensive margin or Big State’s opponents offensive rebound margin is -0.5 (28.1-28.6)

Now we add the two margins and divide by 2  (+6.7 – 0.5) / 2 = 3.1

3.1 would be the new R number in the equation.

Big State has a steal rate of 10.6% and a defensive steal rate of 9.6%.  The national average steal rate is 9.2%.  

So, Big State’s S Rating would be +1.4 (10.6-9.2).  Their opponents’ S would be +.4% (in this case the higher the number, the worse off it is for the team).

Big State has a turnover rate of 16.8% and a defensive turnover rate of 18.2%.  The national average for turnovers is 16.9%, so Big State’s turnover rate margin would be 0.1%, and their defensive turnover rate margin would be 1.3%.

So Big State’s T Rating would be 0.7,  (.1+1.3)/2

Now we have all the numbers we need to plug into the calculation.

((R*8)+(S*2+((5-Opp S)*2)+(T*4)))/2.75

For Big State, the equation becomes:

((3.1 * 8) + (1.4 * 2 + ((5 – .4) *2) + (0.7 * 4)))/2.75 = 14.4

Big State’s R+T Rating would be 14.4, which is about average for an NCAA Tournament Team.  We must at this point look at their schedule strength to see if it merits worthiness against teams most likely to advance into additional NCAA Tournament rounds.

So, by now you are maybe wanting to see some real R+T Ratings?  We are going to show you both the old and new R+T Ratings for the current top 20 teams in the nation.

Here is the old R+T list with the schedule strength.  For schedule strength, 50.0 is average.  55.0 and higher means the team has played a tough schedule.  Below 45.0 means the team has played a weak schedule.  Usually national champions have a strength of schedule between 56 and 62, and most Final Four Teams have strengths of schedule between 52 and 62.

Old R+T

Team

R+T No.

SOS

Gonzaga

24.6

53.9

Houston

23.0

55.8

West Virginia

20.6

60.4

Kansas

17.0

62.3

Baylor

17.0

59.4

Duke

16.5

58.6

San Diego St.

15.9

53.6

Louisville

15.3

57.6

Colorado

14.4

57.6

Maryland

13.1

59.9

Florida St.

12.8

57.9

Butler

11.9

59.7

Kentucky

11.9

56.7

Penn St.

10.3

59.8

Dayton

9.4

54.4

Iowa

9.4

60.8

Marquette

8.1

59.8

Villanova

7.5

60.0

Seton Hall

4.9

60.4

Creighton

2.2

60.3

 

Looking at the old R+T, the Big East appears to be a bit overrated this year.  The four Top 20 teams with the lowest R+T Ratings are all Big East teams.

Until last night, Duke had a much more impressive R+T than they do today, but losing by 22 to North Carolina State, and getting outrebounded and committing more turnovers and having the ball stolen more against the Wolf Pack led to the Blue Devils dropping down to sixth.

Gonzaga’s R+T is about where it was when the Bulldogs advanced to the National Championship Game against North Carolina a few years back.  At the moment, their schedule strength is a tad too low, but GU has games remaining against Saint Mary’s and BYU and likely another game against one of the two in the WCC Championship Game.  The Zags’ SOS could move up a little.

 

 

New R+T Rating

 

Team

R+T Rate

SOS

West Virginia

26.5

60.4

Gonzaga

21.5

53.9

Houston

20.9

55.8

Baylor

18.7

59.4

Duke

18.3

58.6

Colorado

15.3

57.6

Kansas

14.4

62.3

Florida St.

12.7

57.9

San Diego St.

12.7

53.6

Louisville

11.9

57.6

Maryland

10.7

59.9

Iowa

9.6

60.8

Penn St.

8.6

59.8

Butler

7.6

59.7

Villanova

5.7

60.0

Marquette

4.1

59.8

Kentucky

3.8

56.7

Seton Hall

3.1

60.4

Dayton

1.6

54.4

Creighton

-5.5

60.3

 

The new R+T gives a little more credit to three of the Big East teams.  Obviously, lower possessions per game in the Big East are partly to blame for lower counting stats, but on the whole, this does not look like a great potential year for the Big East.

Look at the top four teams here.  All four are teams that are west of the Mississippi River.  There hasn’t been an NCAA Champion from west of the Mississippi River since Kansas in 2008.  There hasn’t been an NCAA Champion from west of the Rockies since Arizona in 1997.  Did you know that the last 11 NCAA Champions came from the Eastern Time Zone?  And, did you know that the last NCAA Champion from the Pacific Time Zone was UCLA in 1995?

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