Since more members of a house have the potential to earn more points for the House Cup, the house multiplier evens the playing field. The multiplier is a ratio of all point-earning students to non-point-earning students, and provides an incentive for everyone to be as active as they can possibly be. The multiplier is needed to adjust size differences between the four houses.
As soon as students earn house points, they will count for the house cup and house multiplier. It doesn't matter where (classes, contests, quidditch etc.) these points have been earned, or if they are positive or negative. Students who have not earned any points in the past 90 days will not count for the house multiplier, but the old points stay. As soon as more points have been awarded, this student will count again for the house multiplier. There are no exceptions, and the whole procedure is fully automatized.
All students are encouraged to do their classwork, homework, and to participate in HOL-wide contests or events.