PCC
Q. What is the playing conditions calculation (PCC) and how does it work?
A. At the end of each day, the playing conditions calculation takes place automatically to determine if scores made at the course were significantly higher or lower than the expected scores of the players who made them, primarily due to weather and/or course set up.
If scores were abnormally low or high, a PCC adjustment between -1 and +3 will be applied in the calculation of Score Differentials™ of everyone who played that day. A negative (-) adjustment means the course played easier than expected and a positive (+) adjustment means the course played more difficult than expected. A PCC of 0 means the course played as expected, which will be the case on most days.
The PCC: Uses scoring data so no action is required by the club/course staff or golfer (except for posting scores),
Includes only scores made by players with a Handicap Index® of 36.0 or below,
Considers both 9-hole and 18-hole scores in the calculation, and
Only takes place if at least 8 scores were posted on a given day.
(Rule 5.6, Rules of Handicapping)