The further from the center the rating, the more ability in the area the user possesses.
Official ratings are not available for each individual, in these circumstances the user will be marked with a rating of "Unknown." Total Ability refers to that ninja's stats across all jutsu fields, strength, stamina, etc. and other unknown factors. This number is more than a sum total of total statgram stats. The Latent Potential is what the ninja possess to gain and use jutsu knowledge. Finally is the ninja's general Luck in life and battle. These ratings stem from Databook 1. No similar stats were provided in Databook 2. The rating is on a 5 point scale, each bar represents one point. In the below example for Haruno Sakura, her Total Ability (TA) is currently at a rating of two, she has a high Latent Potential to excel with a rating of 4 and she has a Luck rating of 3. Note that if one added Sakura's Pre-Exam Databook 1 statgram stats it would seem she should have a rating of "3" rather than "2". This means other factors must play into this number. To take into account these differences and to account for the out of date nature of the TA stats, there is the Unofficial TA rating which we use to add the most recent statgram stats.
Total Ability (TA)
Statistics information gathered from Official Manga Databooks