Points per game
PPG (or Points Per Game), is the single most common indicator of an individual player's ability.
Computation
PPG is computed by taking the total number of points scored by a player and dividing by the number of games played.
Variations
A common variation for timed tournaments is PPTH, or Points Per Tossup Heard. Because each player hears a different number of questions in timed tournaments, PPG can be outrageously skewed towards players who hear more questions in the same number of games. PPTH divides total points by the number of tossups heard, to correct for this difference in the number of questions heard.
PP20H, or Points Per 20 Heard, is a variant of PPTH. This statistic normalizes PPTH to give an estimate of what a player would have scored if the format was 20/20 untimed rather than a timed tournament.
Each individual statistic (PPG, PPTH, PP20H) can be converted to a team statistic by replacing the total points scored by an individual with the total points scored by a team. These team statistics are often considered a better indicator of team strength than their individual counterparts are of individual strength.
Criticism
Many individuals in the quizbowl community no longer subscribe to the idea that the player with the most PPG is the best player in the tournament. There are a number of reasons why a player's PPG may be artificially inflated; these include non-existent or weak teammates, weaker competition, and vulturing.
PPG also does not account for the shadow effect, and so players' PPG may be artificially depressed due to strong teammates or unbalanced team composition.