The USTA has traditionally used the "all factors" method of seeding. It gives heaviest weight to head-to-head matches and to indirect results thus a close loss to a strong player could weigh more heavily than a win over a lesser player.
PPR standings alone should not determine seeds as experience has clearly demonstrated that points are a poor predictor of outcomes. (It's not uncommon for lesser players to earn more points from frequent play than world champions who play fewer tournaments.)
Use standings as a starting point then "drill down" to individual player records to review specific wins and losses without regard to points.
Give consideration to players "moving up" from a younger age category and to strong players who haven't played recently;
"Eligible" players appear as the default, but "ineligibles" (those who've not played enough nationals) should also be considered;
Doubles standings are prepared both for teams (preferable) and individuals (use ― with judgment ― for teams without a record);
Rely on the National 12-Month Rolling Standings List solely as they list every match.
Effective January 1, 2012 the maximum number of seeds permitted is as follows:
97-128 players: 32 seeds
33-96 players: 16 seeds
17-32 players: 8 seeds
9-16 players: 4 seeds
3-8 players: 2 seeds
Here's how to find any player's record using this web site:
Click here to display the current National Standings;
Use the appropriate 12-Month Rolling Standings List;
Click on the player/team name to view their complete record;
Review records for ineligible players too (Use the Show dropdown in the upper left);
Strengthen your seeding by getting reliable outside advice. Here are good practices that Category I Nationals must observe:
Consult the appropriate Seeding Assistants for your age divisions. They are knowledgeable and available for advice;
Discuss the seeds with some of the stronger players before posting them;
Post the seeds a few days before the draw to give players a chance to point out oversights;