calculate_pi_ratings: Calculate Pi Ratings

In larsvancutsem/piratings: Calculate Pi Ratings for Teams Competing in Sport Matches

Description

This function calculates dynamic performance ratings called "pi ratings" for sport teams in competitive matches. The pi rating system was developed by Constantinou and Fenton in their research paper 'Determining the level of ability of football teams by dynamic ratings based on the relative discrepancies in scores between adversaries'.

source: http://www.constantinou.info/downloads/papers/pi-ratings.pdf

Usage

calculate_pi_ratings(teams, outcomes, lambda, gamma, b, c, return_e)

Arguments

teams	an (n x 2) character matrix, contains unique names for the respective home and away teams in n subsequent matches
outcomes	an (n x 2) numeric matrix, contains the points that the respective home and away teams scored in n subsequent matches
lambda	a constant, the learning rate for performance from recent matches, default value: 0.035
gamma	a constant, the learning rate for performance from home to away and vice versa, default value: 0.7
b	a constant, logarithmic base, default value: 10
c	a constant, default value: 3
return_e	a boolean variable, conditions the function to return either the mean squared error when return_e = TRUE, or the pi ratings when return_e = FALSE, default value: FALSE

Value

either an (n x 2) matrix containing the pi ratings for the teams in the n input matches or the mean squared error for the specific parameter setting, conditional on boolean parameter return_e being FALSE or TRUE

Examples

# toy example
teams <- matrix(c("team A", "team B", "team B", "team A"), nrow = 2)
outcomes <- matrix(c(1, 3, 2, 1), nrow = 2)
calculate_pi_ratings(teams, outcomes)

larsvancutsem/piratings documentation built on June 4, 2019, 5:20 p.m.