Making Sense of the Unveiling of the NCAA Men’s Basketball NET Rankings

    It's new, it's different and it has Loyola Marymount ranked No. 10 in the country? We're talking about the NCAA men's basketball NCAA Evaluation Tool

    November 26, 2018

    It’s new, it’s different and it has Loyola Marymount ranked No. 10 in the country?

    We’re talking about the NCAA men’s basketball NCAA Evaluation Tool (NET) rankings, which were approved by the NCAA and rejoiced as a replacement for the RPI, but vaguely understood by many. They finally became tangible on Monday with the first-ever release of the rankings.

    We scrolled through the entire No. 1 to No. 353 rankings, reviewed the criteria that go into the NET calculations and tried to establish some takeaways from Monday’s announcement.

    As a reminder, the NET replaces the RPI as the primary sorting tool in Division I men’s basketball after consultation with the DI Men’s Basketball Committee, the National Association of Basketball Coaches (NABC), analytics experts and Google Cloud.

    There are five primary components to the NET ranking, listed in descending order of weight in the calculation:

    • Team value index (based on game results that factor in opponent, location and winner)
    • Net efficiency (offensive efficiency minus defensive efficiency)
    • Winning percentage
    • Adjusted win percentage (weighted value based on location and result)
    • Scoring margin (point differential capped at 10 points for each game)

    Also of note is that the date and order of games are not factored into the NET rankings. That means a win on November 10 has the same impact and value as if it had occurred on March 10.

    The Quadrant system, an organizing method adopted last season that separates wins and losses into four categories, will still be used, but the rankings used to establish the quadrants will now be determined by a team’s NET ranking, not its RPI ranking.

    Here’s a reminder of the Quadrant system:

    • Quadrant 1: Home 1-30; Neutral 1-50; Away 1-75
    • Quadrant 2: Home 31-75; Neutral 51-100; Away 76-135
    • Quadrant 3: Home 76-160; Neutral 101-200; Away 136-240
    • Quadrant 4: Home 161-plus; Neutral 201-plus; Away 241-plus

    Here are the top 10 teams in the NET rankings through Sunday.

    Rank School Conference Record
    1 Ohio State Big Ten 6-0
    2 Virginia ACC 6-0
    3 Texas Tech Big 12 6-0
    4 Michigan Big Ten 6-0
    5 Gonzaga WCC 6-0
    6 Duke ACC 5-1
    7 Michigan State Big Ten 5-1
    8 Wisconsin Big Ten 5-1
    9 Virginia Tech ACC 5-0
    10 Loyola Marymount WCC 7-0

    Now, time for some takeaways.

     

    It’s November 26

    The season is barely three weeks old. Some teams have played three games, others have played eight. For a sport with 353 teams whose schedules offer an incredible disparity in terms of competition and location of their non-conference games, it’s understandable if the rankings don’t align with the AP Top 25 poll, kenpom.com rankings, the eye test or any other ranking system at this point in the season.

    So if you’re concerned that Ohio State is ranked No. 1, Gonzaga is No. 5, Loyola Marymount is No. 10, Kansas is No. 11 and Kentucky is ranked No. 61, just wait a day because the NET rankings will change tomorrow. And the day after that and every other day for the rest of the college basketball season.

    As the number of games increases for every team, odds are you’ll start to think the rankings make more sense.

     

    However, we’ll always be somewhat in the dark

    Even as the rankings begin to make more sense as the season continues, college basketball fans will likely always have their share of questions about just how the formula is calculated and weighted.

    We know how the RPI was calculated:

    RPI = (winning percentage * 0.25) + (opponents’ winning percentage * 0.50) + (opponents’ opponents’ winning percentage * 0.25)

    But we don’t know the exact formula that computes a team’s NET ranking and how the various factors are weighted. For example, the team value index, which is listed as weighing the most heavily among the various factors in the NET calculations, is described as an “algorithm set up to reward teams who beat other good teams” in a graphic the NCAA has shared to explain the NET to fans.

    That description represents an idea everyone can get behind, but the algorithm is unknown to everyone but the select few who are in the braintrust at the NCAA and Google.

    To put it simply, it’ll take the blind trust from players, coaches and fans that the NET formula is fair and an improvement from the RPI, but don’t be surprised if there’s a call for transparency on Selection Sunday when schools perceive that they were snubbed from the NCAA tournament.

     

    Scoring margin is capped, but net efficiency isn’t

    The NCAA capped scoring margin at 10 points “to prevent rankings from encouraging unsportsmanlike play, such as needlessly running up the score in a game where the outcome was certain.” However, scoring margin has the smallest weight in the calculation of the NET ranking – behind team value index, net efficiency, winning percentage and adjusted win percentage.

    Net efficiency, which is a team’s offensive efficiency minus its defensive efficiency, isn’t capped. So even if a team wins by 25 points and the scoring margin is capped at a 10-point victory, the winning team still has the net efficiency of a team that won by 25 and that will weigh more heavily than the capped scoring margin.

    It’s also worth noting that net efficiency isn’t adjusted based on the quality of an opponent, as it is on kenpom.com – a popular college basketball advanced metrics site that’s often cited in discussions by media and diehard fans.

     

    Road/neutral wins (especially against good teams) matter

    To once again stress points made earlier, it’s early in the season and we’re learning how to analyze and discuss the NET rankings together for the first time. But it looks like there’s a significant correlation to playing and beating quality teams away from home and a team’s NET ranking.

    Ohio State, the No. 1 team in the country through Sunday according to the NET rankings, has two true road wins against Cincinnati (No. 46) and Creighton (No. 36). Those wins, plus a raw net efficiency – meaning not adjusted for competition – of plus-31.5 (due to a raw offensive efficiency of 115.8 minus its raw defensive efficiency of 84.3 through six games), likely play a major role in the Buckeyes’ top ranking.

    The top five teams are all undefeated with two or three wins away from home. The teams ranked No. 6-8 – Duke, Michigan State and Wisconsin – each have a 5-1 record with their losses coming by single digits on a neutral court against a team that’s ranked in the top 11 in the NET.

    Notre Dame, which debuts at No. 19, is the highest-ranked team that doesn’t have a single win on the road or on a neutral court as of Sunday.

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