Definitions for: R
Rating
Example of teams’ internal factors: recent form, motivation, available players and their fatigue, etc.
Example of teams’ external factors: weather conditions, distance the visiting team has to travel, motivation of the home crowd, etc.
Return on Investment
A measurement of efficiency of series of bets, expressed in percentage.
ROI = Sum of returns from all bets / Sum of stakes of all bets
Higher the ROI, bigger the profitability of betting. ROI below 100% indicates loss.
Yield basically has the same meaning, so these two terms are usually interchanged. Yield is displayed slightly different, as the profit on investment:
Yield = Sum of profits from all bets / Sum of stakes of all bets
Obviously, ROI - Yield = 100%.
Example: ROI of 112% corresponds to Yield of 12%, and ROI of 97% corresponds to Yield of -3%.
See: Strike Rate.