Tiers

While a team's strength of schedule can give you an idea about how they stack up to competition, how do you know if a team has quality wins or losses?

Tiers can help answer this question.

KenPom defines 2 tiers:

  1. Tier A: a game against a top-50 opponent adjusted for location of the game

  2. Tier B: a game against a top-100 opponent adjusted for location of the game

Why make adjustments for location?

Home court advantage exists in college basketball. KenPom gives a flat 3.75 points for the home team.

The 3.75 points was included in KenPom's announcement of using AdjEM for ratings prior to the 2016-17 season. It's explained at the end of this blog post.

For example, in the 2016-2017 season, Duke would be expected to defeat the average Division-I team by about 24 points on a neutral court.

If Duke is playing host to the average Division-I team, it's AdjEM jumps to about +28. This means at home, Duke would be expected to defeat the average Division-I team by about 28 points.

This is why adjusting for location is important.

KenPom details this more in this article and shares this example:

Beating the 90th-ranked team on the road is about as difficult as beating the 50th-best team on a neutral floor, which is roughly as difficult as beating the 20th-best team on one’s home floor.

KenPom does hint towards sharing site-specific home-court advantage values in the future too.

The RPI Can Be Misleading

The RPI (Rating Percentage Index) is built to measure a team's strength of schedule and how that team performs against that schedule.

Since 1981, the RPI has been used by the NCAA Selection Committee as one of the main factors in determining at-large selections for the NCAA Tournament.

The RPI has 3 components each with a percentage of importance:

  1. A team's winning percentage (25%)

  2. A team's opponents' winning percentage (50%)

  3. Winning percentage of a team's opponents' opponents (25%)

A team's strength of schedule is 75% of this calculation. The problem?

The RPI doesn’t include location when measuring a team's strength of schedule.

The RPI promotes a team's record against top-50 teams. But there is no consideration for a where a game is played. Home court advantage doesn't exist in the RPI.

Examples

Let's compare 2 teams for the 2016-2017 season:

  1. Illinois State

  2. Providence

Using the RPI

Illinois State:

Providence:

Providence earned the 11-seed in the NCAA Tournament and played USC in a play-in game. Illinois State missed the 2017 NCAA Tournament and didn't earn an at-large bid.

Providence is viewed as better because it has 6 wins over the RPI Top-50 compared to 1 Illinois State victory.

Using Tiers

Illinois State:

Providence:

Illinois State was 1-3 against Tier A opponents and 4-1 against Tier B opponents.

Providence was 2-9 against Tier A opponents and 6-1 against Tier B opponents.

Illinois State won 25% of their games against Tier A opponents. Providence won 18% of their games against Tier A opponents. It had 7 more chances to earn a Tier A win than Illinois State.

Who is the better team according to strength of schedule?

This is why the RPI can be misleading, and tiers exist to rate strength of schedule.

Question, concern, or spot a typo? Please send me an email and let me know.

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