The National Tennis Rating Program (NTRP) is used by the USTA to rate players for the purposes of having them play at the the proper levels that will foster competitive play between players at the same level. Levels are defined from 2.5 up to 7.0 in 0.5 increments, a 2.5 being a beginning player and a 7.0 being a touring pro, but you will typically see adult league play in primarily the 2.5 thru 5.0 levels.
I started playing USTA League in 2010, and being a bit of a stats geek and having done ratings systems for other sports, I soon became intently interested in the NTRP system and how the ratings were calculated. The USTA only publishes ratings to the half point and only updates them at the end of the year (early start ratings are published in some sections, or DQs can occur for new players that have underrated themselves) and I wanted to calculate finer grained ratings and be able to see them throughout the year, so the Estimated Dynamic NTRP Rating was created.
I started estimating ratings for my local league, then my local area, and was fortunate to go to Nationals in 2011 so naturally looked at ratings from other sections in order to scout opponents. Soon there after, I started generating reports showing a players estimated dynamic rating along with a summary of their stats from their league tennis matches and also a chart showing how their dynamic rating changed match by match. Originally, it was just in my section, the Pacific Northwest, but quickly grew to cover any and all USTA sections.
Today, I can generate an Estimated Dynamic NTRP Rating Report for any USTA League player and can also generate Team Reports to show the ratings and related stats for a team which can be a great way to scout opponents. I also regularly blog about ratings and playoff related USTA League topics.
Other resources on this site include an NTRP Ratings FAQ and I have a record of the USTA League National Champions from 2013 and 2014.
Note that this site and the ratings published are in no way affiliated with the USTA. These ratings are for information and entertainment purposes only and may or may not be close to the actual rating maintained by the USTA, although the accuracy has proven to be well over 90%.