Methodology



  • Data

    • 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.

  • Ratings


    • 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.




  • Performance Factors


    • Wickets per run
      This is a moderate factor that gives the highest value to a high number of wickets taken with the least runs conceded. By tieing the factor with runs conceded this avoids rewarding wickets taken after conceding a significant number of runs.

    • Economy
      Major factor in limited overs matches. This rewards lower economy rates compared to other's in the team as well in absolute terms. The value is scaled by the number of overs bowled. A bowler who is economical but doesn't pick up a wicket will get a higher rating than one who gets a few wickets but is expensive due to this factor.

    • Wickets quality
      This factor that considers the total current batting rating of the batsmen dismissed. This factor is adjusted by the runs conceded to avoid unduely rewarding expensive returns where a bowler dismisses a quality batsman after he has done damage.

    • Batting quality
      This factor that considers the current rating of the batting line-up faced. Adds increasing value to more significant bowling performances to avoid rewarding unsuccessful and expensive returns against good batsmen.

    • Incomplete innings
      This factor comes into play significantly in incomplete innings (< 10 total overs bowled). If the bowler has bowled less that 2 overs, it is deemed an incomplete performance where he did not get the opportunity to make an impact. In these cases, the bowler's current bowling rating overrides the innings performance to avoid unduely penalizing the performance. This functions similarly to a batsman being not out at the end of an innings.

    • Match status
      This factor rewards contributions made in significant matches like finals. League knock-out matches are the most highly rewarded.

    • Result
      This factor recognizes significant contributions made in wins and ties. Positive results against higher rated teams are rewarded more than against lower rated teams, using the current rating at the time of the match of the opposition team.

    • Milestone
      Minor factor that adds a bonus to 3-wicket performances.