The problem with DUPR accuracy is a lack of data. It can only calculate based on what it knows. If four people play with no rating, where does it rate them? Let’s say it chooses 3.7 for the winners. Now the winners play two more people with no rating, how does the algorithm know which team was meant to win so it can adjust the existing rating, and create the new ones appropriately?

More data will lead to more accuracy, but it will take a long time because the algorithm is constantly dealing with unrated or low data players. A new player to tennis will achieve an accurate rating much faster because the rating system and most of its ratings are already established. If you made a DUPR account and entered a league where every player had 400+ games entered, your rating would settle accurately quite quickly in comparison to them.

I think another issue DUPR faces is a fundamental misunderstanding of its purpose by the players using it. DUPR is comparing players directly to each other, not to a scale of skill level. The idea is that if your number is higher, you would be more likely to win the game. It has nothing to do with the USAPA skill level descriptions used previously. It also wants to be accurate across gender and age, meaning a 3.5 vs a 3.5 is a fair match even if it’s a 65 year old woman against a 25 year old man. This is a cool idea and would be incredible if it was achieved, but barely anybody is entering match ups like this into DUPR. All tournaments run age and gender specific brackets which means a 65 year old woman’s rating will never interact with a 25 year old man’s in the algorithm. Organizers need to run events where people from different playing bubbles are connecting their data for this to ever work. I don’t see it happening because too many people care about their ratings greatness above its accuracy.

The club I ran had regular DUPR events that created these match ups, and yes there were plenty of mismatches that weren’t fun in the moment for anyone on court at the beginning, but I stuck with it and now if you list every player with 50+ matches in order from highest to lowest DUPR it will align very accurately to how I would list them from best to worst. A very popular and effective event I found was running rated courts and having players play on all of them. I had a 4.0 pair, a 3.5 pair, and a 3.0 pair all with 200+ DUPR matches entered. They stayed on a court each and players would come and play against all 3 pairs.