The CHSAA Postseason Seeding & Selection Index is a tool used by a range of sports each season to help select and seed their postseason brackets.
Below are answers to common questions about the system
What is the CHSAA Seeding Index?
The Seeding Index combines ranking systems to form an average, and then rank teams according to that average. The two systems used are the CHSAA RPI Standings and the MaxPreps rankings. (Find answers to FAQs about RPI here.)
Where can I find this data?
The standings automatically update with new data, when it is available, on the Seeding Index page.
How often does data update?
The RPI feed updates every hour. The MaxPreps rankings update on Mondays and Thursdays.
The Seeding Index page shows the time each feed was most recently updated.
What is the source of the MaxPreps rankings data?
The CHSAA office runs the MaxPreps rankings internally. This is now standard for all sports, following football's change to use this process in Fall 2024. (This change was recommended by the football committee, and then approved by the Legislative Council.)
Note: Because CHSAA runs the rankings internally at different times that MaxPreps runs them — and because CHSAA includes forfeits in the calculation, while MaxPreps does not — the data shown on the MaxPreps.com may differ from what is being used in the Seeding Index.
For the most up-to-date MaxPreps rankings used in the Seeding Index, visit the MaxPreps rankings page.
How is the data combined?
Each data source accounts for half of the final formula, so that means both the RPI and the MaxPreps systems share 50% weight.
In order to accuractely compare and combine the two system, each team's MaxPreps and RPI ranking values are normalized within their classification. These values are then averaged to create their final rating, which is then ranked.
The type of normalization used is called Min-Max normalization, and places all values between a range of 0 and 1, while preserving the relationships between the ranking systems' orginal ratings.
The first step of this normalization is to identify the maximum (Max) and minimum (Min) values within each classification of each ranking system.
Note: If the minimum value of a MaxPreps ranking is negative, all values in that classification need to be scaled so that the minimum is 0. To do this, add the absolute value of the lowest value within the classification to all MaxPreps ratings within the classification.
Here are the complete steps:
1. Identify the Max and Min of the RPI ranking system within each classification.
2. Identify the Max and Min of the MaxPreps ranking system within each classification.
3. If the Min MaxPreps value within a classificaiton is negative, add the absolute value to all MaxPreps ratings within that classification. Then identify the new Max and Min of the MaxPreps ranking system within each classification
4. For each ranking system, first subtract the overall Min from the team's rating. Then divide this total by the overall Max minus the overall Min, also known as the Range. Here is the equation:
5. Average the result of each ranking system's normalized value for each team.
6. Rank each team's average within each classificaiton.