- The following franchises are considered:
- IPL (Indian Premier League, from 2008)
- BBL (Big Bash League, from 2011)
- CPL (Caribbean Premier League, from 2013)
- The IPL is taken as the standard of quality franchise T20 cricket, so only leagues that relatively match its quality with siginificant international player presence are considered.
- FT20 scorecards are parsed to rate every bowling performance. Scorecard information is sourced to generate an accurate assessment of each player's performance.
- Match results are used to generate team ratings. Fielding performances are evaluated by parsing detailed text commentary (More detail here). Win shares are calculated by attributing over-by-over team match odds changes to the appropriate player.
- Current Top FT20 Bowlers:
This is evaluated using a weighted average of a bowler's performances. More weight is given to recent performances with past performances diminishing in value with time. Unestablished bowlers that have played less than 20 innings are penalized to avoid cases where a few highly rated innings can catapult a newer bowler to the top of the pile.
- Best FT20 Bowling Careers:
This evaluates overall careers by calculating the average performance rating of each bowler, with a bonus given to career longevity and a penalty for careers of less than 20 matches (increasing penalty for lower matches played).
- Best FT20 Bowling Performances:
This is a list of the highest rated bowling performances calculated using the factors given below.