LaxMath is devoted to rating high school and college lacrosse teams. We have chosen two methods: (1)
Power Ratings (PR) based on goal margins
of difference and (2) Rating Percentage Index (RPI) based on won-loss records. Championship
probabilities are based on power ratings,
whereas at-large tournament selections are based on the RPI. From either system we derive strength of
schedule (SOS)
and quality wins factor (QWF). We recommend the former for high schools and the latter for college
tournament selections.
Championship Probabilities
Each team has a probability of winning the championship in their division based on the power ratings.
The games unplayed are assigned a score based on a random number and the difference in the two teams power
rating.
Multiple simulations for a season are recalculated and the net result is the championship probability.
This probability is an indication of whether a team has any chance of being the best in its division.
Just click on the college or high school navigation button and select a division
Power Rating
Power ratings, unlike RPI ratings are not based on Wins and Losses but rather the goal margin of victory
versus opponents.
The difference between two opponents power ratings is the predicted goal difference if two teams played each
other on a neutral site.
Just click on the college or high school navigation button below, select division and RPI button.
Rating Percentage Index (RPI)
RPI is a measuring parameter used by the NCAA to determine college tournament invitations.
It is based on won-loss records and not the score or goal margins of victory.
We provide these values for not only colleges but, as a courtesy to our fans, high school as well.
We do not recommend using the RPI method to evaluate strength of teams because it ignores
the most critical piece of data and that is the game score. As an example: if two teams play identical
records and the first team overwhelms its opponents whereas the second team barely defeats it opponents,
the RPI calculations has both teams of equal strength. The power ratings, on the otherhand,
has the first team of much higher strength than the second based on the goal margin of victories.
Just click on the college or high school navigation button below, select division and RPI button.
Strength of Schedule (SOS)
SOS is a measure of how difficult a team’s schedule is.
There are two ways of computing the strength of opponent and the first is based on the opponent’s power
ranking and the second is based on the RPI ranking.
Just click on the college or high school navigation button below, select division and SOS button.
Quality Wins Factor (QWF)
QWF is a measure of wins and losses based on the opponent’s strength. A victory counts more against a
higher ranked opponent than a lower ranked opponent and a loss against a higher ranked opponent counts less
than a loss against a lower ranked opponent.
There are two ways of computing the strength of an opponent, the
first is based on the opponent's power ranking and the second is based on the opponent's RPI ranking.
Team Schedule, Scores, and more
A list of all games played by a team with the score and other attributes
such as average goals (offensively, defensively) and performance versus top teams is listed. Formost is
over-achieved or under-achieved performance for each gamei played.
Just click on the college or high school navigation button below, select division Power Rating button and
finally the team’s hyperlink
Game Performance
Each game is examined to determine if a team over- performed (+.++.+++) or under-performed (-,--,---) based
on the power ratings of the two teams and home-field advantage.
Just click the college or high school navigation button below, select: division, power rating button and
team.
NCAA Selection Process
The NCAA evaluates teams for selection to the NCAA Championship Tournament based on RPI, SOS and QWF. We
present these parameters and employing a formula that weighs them equally,
we predict the at-large order of selection for men and women varsity divisions. This applies primarily to
college although the relevance to high school is not significant since state
committees generally do not consider these factors.
Just click on the college navigation button below, select division and the selection criteria
hyperlink.