Conversion metrics are a measure of how hard a given tournament is compared to the field it attracted. While no single conversion metric has been promoted as the best indicator of difficulty, several different conversion metrics combine to give an overall picture of the tournament.
Conversion metrics are often cited to prove a tournament's relative accessibility.
Tossup Conversion Rate
The tossup conversion rate simply gives the percentage of tossups correctly answered over the entire tournament, by all teams participating. Many people choose to leave out tiebreaker and finals games when computing this as only a small percentage of the field plays these games.
Average Bonus Conversion
The average bonus conversion adds up the total number of bonus points earned by all teams at the tournament and divides by the total number of bonuses earned.
Median Bonus Conversion
Because the average bonus conversion can be severely skewed by a few extremely good or extremely poor teams, the median bonus conversion is often used as a substitute for average bonus conversion. Median bonus conversion is found by taking the bonus conversion of every team participating at the tournament and computing the median.
Average/Median Points Per Game
The average points per game adds up the total number of points scored by all teams and divides by the number of games played. As with bonus conversion, a median points per game is sometimes used as a more accurate conversion metric.
APPK, or Adjusted Points per Thousand Available, is a conversion metric popularized by Matt Weiner that allows comparisons across formats. The total points scored by the field, discounting all powers and negs, is divided by the number of games. The result is then divided by the theoretical maximum total score possible in a single game (again, discounting any powers and negs) and multiplied by 1000.
Words per Buzz/Adjusted Words per Buzz
The most promising yet-to-be-developed conversion metric, Words per Buzz quantifies exactly how long it takes players to buzz in by averaging the number of words it takes for the first player to buzz in. A Words per Buzz metric allows individual tossups to be scrutinized to check whether certain clues were placed too early, diagnose difficulty cliffs, and provide data for placement of power marks at future tournaments.
Adjusted Words per Buzz is a variant of Words per Buzz in which the Words per Buzz for each tossup is divided by the total word count of that tossup. This allows for comparisons across different tossup lengths.