Understanding the UTR Powered by Oracle Algorithm
Author: Justin Stocks-Smith, Universal Tennis
UTR Powered by Oracle is a modified elo rating system that promotes fair and competitive play across the tennis world. Players are rated purely based on actual results, not age, gender, nationality, or socioeconomic status.
What is a UTR? Why should I have one?
UTR (Universal Tennis Rating) is a number between 1.00 and 16.50 that provides a real and accurate measurement of a player's skill level. When you determine your skill level, you can find hits, events, and tournaments where you’ll have fun, play competitive tennis, and improve your game. All you need to know is your UTR!
One match result is all it takes to receive a projected UTR and after approximately five matches, the rating becomes reliable. A player’s UTR will change over time as more of their matches are added to the system.
How is it calculated?
UTRs are purely result-based and are calculated using a player's last 30 eligible match scores from within the last 12 months. For each eligible match, the algorithm calculates a match rating and a match weight and a player’s UTR is the weighted average of all the match ratings. Please note that more than 30 matches may be used in cases where the 30th match happens to fall within a tournament with additional matches. In this scenario all matches from the tournament are counted and consequently they are all taken off at the same time as well.
Calculating Match Rating
Match ratings are calculated by taking into account the UTR difference between the opponents and the percentage of games won by each player. Given the UTR difference, the algorithm expects a certain percentage of total games won. The player who performs better than the algorithm’s expectation will see their match rating go up while the other player’s match rating will go down by the same amount. For example, if your opponent's rating is exactly the same as yours then the system expects you to win exactly the same number of games as your opponent. But if you end up winning more games than them then that will help your match rating. Similarly, if your opponent is X levels below you and the system expects you to win 6-2, 6-2 and you end up winning 6-1, 6-1 then that would help your match rating as well. The same scale applies to playing against a higher-rated opponent. So if the system expects you to lose 6-3, 6-3 but you lose 6-4. 6-4 instead then that will boost your match rating as well. In all these cases, how much your match rating goes up will depend on how far above expectation your total game count in the match was. Similarly, doing worse than expected in these matches will hurt your match rating.
Calculating Match Weight
The following factors are used in the match weight calculation:
Format – As the match format increases in length, more weight is given. A match with a three-set format receives more weight than a match with an eight-game pro set format.
Competitiveness – As the UTR difference between players increases, less weight is given. For example, imagine a player with a UTR of 6.00. A match played against an opponent with a UTR of 5.00 or 7.00 receives more weight than a match played against an opponent with a UTR of 4.00 or 8.00.
Reliability – As the reliability of the opponent’s UTR increases, more weight is given. A match played against an opponent who competes often and thus has a reliable UTR receives more weight.
Time Degradation – As prior matches get older, less weight is given. Since the algorithm is a representation of current form, it gives more credit to matches played within the last few months.
What is the best way to improve my UTR?
Compete Well – Competing well in matches is the easiest way to improve your UTR. So you should always try to win as many games as possible even if you know you are going to lose the match. It does not matter whether you play higher- or lower-rated opponents; you can improve your UTR either way by winning more games than expected.
Play Often – The more matches you play, the quicker your UTR will reflect your current form. It is also best to play against opponents who are close to your rating regardless of whether they are above or below you.
Be Patient – Since your UTR is a rolling weighted average, the effect of new results is slightly lagged. Your UTR may not fully reflect a recent outcome right away, but it will over time.
What is the impact of playing against opponents rated lower than I am?
Playing against lower-rated opponents does not necessarily hurt your rating. In fact, in some cases, it could boost it. It all depends upon the percentage of games you win and how much lower the opponent’s UTR is than your own. If the opponent is rated too far below you and you win the match easily, winning a high percentage of games,that won’t lower your rating, because that is the expected outcome. It can actually even raise your rating if you win a higher-than-expected percentage of games. However, if you play a close match against that opponent, that could lower your rating.
What is the impact of playing against opponents rated higher than I am?
Playing against higher-rated opponents does not necessarily lower your rating and in some cases can actually improve it. Here again, it depends upon the percentage of games you win, and how much higher the opponent’s rating is. If the opponent is rated too far above you and they win the match easily by winning a high percentage of games, that won’t hurt your rating, as it is the expected outcome. But your rating can get a boost if you end up playing a close match. On the other hand, such a match can lower your rating if you end up not winning a high enough percentage of games.
Why did my rating change when I haven't played recently?
UTR currently recalculates daily - there can be a variety of reasons why a change (up or down) would occur. Some of these reasons could include:
a) You played a player that was unrated/projected and their rating has become more reliable through more play.
b) Ratings are calculated every day using the current ratings of the opponents. So changes in their ratings can have an impact on your UTR as well.
c) Scores from more than 12 months ago fell off your record
Remember, UTR is a measurement of player skill today.
Why don't some of my matches count towards my UTR?
The algorithm excludes matches in which a) a player withdraws before the match starts, b) the match starts but neither player wins at least four games (due to a withdrawal/retirement), or c) there is a UTR difference of more than 2.50 and the higher-rated player wins as expected (i.e., in a blowout). These excluded matches still show up on the player profile but are not used in the rating calculation.
Do unfinished or incomplete matches count towards UTR?
The UTR system does use unfinished or incomplete matches for ratings calculations in cases where at least four games were won by either player before the match was stopped.
How does UTR address walkovers, retirements/withdrawals, and defaults?
Since our rating system is based purely on scores, it does not take into account defaults or walkovers. However, these results are still displayed on the player's profile page along with their other scores. With regards to withdrawals, if a player withdraws either a) before the match starts or b) during the match but before either player wins at least four games, it does not factor into the UTR algorithm. It will, however, be displayed on the player profile. This display will hopefully be a disincentive for the small subset of players who withdraw quite frequently. We are aware of and monitoring junior players abusing the system.
Why does the algorithm exclude matches between opponents with a UTR difference of more than 2.50 where the higher-rated player wins as expected (i.e., in a blowout)?
As the difference in UTR increases, so does the likelihood the higher-rated player wins the match easily. Our data indicates matches with a UTR difference of more than 2.50 are almost certain to be blowouts, and these blowout matches are really not indicative of the specifics of either player’s skill level, so they are excluded by the algorithm.
What if I have played fewer than 30 matches within the last 12 months?
That’s perfectly fine. If you have played only 10 matches within the last 12 months, the algorithm will use those 10. 30 is simply the maximum. If you have played 40 matches within the last 12 months, the algorithm will use the 30 most recent matches.
Why are more than 30 matches being used to calculate my rating?
This occurs when the 30th most recent match was played on the same day as the 31st most recent match. The algorithm does not try to determine which one to keep, so it keeps them both. They will fall off together when the next match is added.
I don’t play very often. Can I still have a UTR?
Absolutely. One match is all it takes to get a “projected” rating. After approximately five matches, your rating becomes reliable. A projected rating is shown as a (P) on the player profile.
Are 8-game pro sets and “4-game set” matches used for ratings?
Yes. 8-game pro sets and 4-game mini sets count for ratings calculations, but receive slightly less weight relative to best-of-3 set matches
How are tiebreakers counted by the algorithm?
Set tiebreakers count as one game and 10-point match tiebreakers for the 3rd set count as two games
What is a projected rating? How many matches does it take to go from a projected to a reliable rating?
The algorithm needs approximately five results before it can calculate a reliable UTR. Players with fewer than five results are not yet fully reliable, so they have a “projected” rating. A projected rating is shown as a (P) on the player profile.
Can my rating be changed if it doesn’t look accurate to me?
The ratings are automatically generated by a computerized algorithm and cannot be altered manually. We are able to add or edit incorrect or missing scores on your record, which may impact your rating.
What is the difference between Verified UTR and UTR?
Verified UTR is your official rating. It reflects only matches played in verified tournaments and events. UTR is your unofficial rating. It reflects matches played in verified tournaments/events and other non-verified matches. For example, USTA league/tournament matches count toward Verified UTR and UTR. Casual/friendly matches do not affect Verified UTR; they count only toward UTR.
Verified UTR reflects your 30 most recent match results from verified tournaments and events. UTR reflects your 30 most recent match results from any event.
How does the algorithm work for doubles?
The singles and doubles algorithms are very similar. For doubles, the algorithm compares the average UTR of Team A to the average UTR of Team B. Given the UTR difference between those two averages, the algorithm expects a certain percentage of games won. The team who performs better than the algorithm’s expectation will see their match rating go up. Both teammates see an increase or decrease by the same amount.
Can my UTR be lower than 1.00 or greater than 16.50?
No. To preserve the distribution of player ratings by skill level, the algorithm has upper and lower bounds for UTR.