I have been working on replicating the USTA's Dynamic NTRP ratings for several years and been offering reports since 2012. While I started doing this in my own section (Pacific Northwest), I can now generate reports for players from any section that play USTA League.
For reference, the National Tennis Rating Program (NTRP) is used by the USTA to rate players for the purposes of having them play at the proper levels to maintain competitive play. 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.
The USTA only publishes ratings to the half point and only updates them at the end of the year (mid-year bumps 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 was created.
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%.