Points per bonus
Points per bonus or PPB is a statistic calculated as the number of points earned on bonus questions, divided by the number of bonus questions heard. In most formats, it therefore is between 0 and 30, inclusive.
PPB is conventionally reported to two decimal places. When calculating it, care must be taken to account for any tossups a team might have answered that did not lead to a bonus question, which in many formats means correct tossups answered in overtime. In formats with bonus bouncebacks, PPB conventionally only refers to points on controlled bonuses (i.e., bonus questions following tossups that a team answered correctly), though some tournaments do not properly separate bounced-back bonus points in their statistics.
Application
Because a team's performance on bonus questions is, in principle, dependent only upon themselves and not upon their opponents, some tournaments use PPB to break ties among teams that played different sets of opponents. Critics of this practice point out that discarding half the game of quizbowl (i.e., tossup performance) tends to skew results, and indeed, actual results do not entirely bear out the idea that PPB correlates better to actual results than does points per tossup heard even among teams with different schedules. Variability in questions and packets can (despite writers' and editors' best efforts) significantly affect both PPB and PPTUH, perhaps more than scheduling considerations: a team's PPB is influenced by which bonuses they happened to hear, and even comparing teams with common opponents on PPTUH is questionable given that such teams will necessarily have played their common opponents on different packets.
The Morlan rankings are based in significant part on PPB.