The
GNAS publishes a set of tables. Each table shows how the scores for each round correspond to a handicap value. There are separate tables for women, men, juniors, recurves, compounds and barebow.
Your handicap is calculated as the average of the handicap values for your three best rounds. So when you shoot a better round than previously, your handicap drops.
Clubs are responsible for operating the handicap system -- there's no central register. Separate handicaps are maintained for indoors and outdoors. Handicaps are used at certain shoots to "level the playing field".
I'm not too keen on handicaps personally.
The
GNAS is currently in the process of revising its handicap tables. Apparently, the copyright of the existing ones belongs to a "D Lane", and it seems this has caused problems.