Methodology



  • Data


    • ODI scorecards from 1971 to date 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. Peak ratings are identified by checking if the rating before and after the particular match considered is lower.

    • 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.

    • Players lose 1% of their live rating if they miss a team match. This is to ensure injured or dropped players do not stay high in the ratings without playing matches.

  • Ratings


    • Current Top ODI 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 ODI Bowling Careers:
      This evaluates overall careers by calculating the average performance rating of each bowler, with a bonus given to career longevity (where playing the most number of years while missing the least percentage of matches gets the most credit) and a penalty for careers of less than 100 matches (increasing penalty for lower matches played). The 95% confidence interval range is shown with a ± after the career rating.

    • Best ODI Bowling Performances:
      This is a list of the highest rated bowling performances calculated using the factors given below.

    • Best ODI Team Bowling Peaks:
      This lists the best bowling attacks by aggregate current bowling ratings of the first 6 players that bowled for the team in a match. Only peaks (aggregate rating before and after lower) are shown for clarity.


  • Performance Factors


    • Wickets per run
      This is a major 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.

    • Wickets per ball
      This factor gives the highest value to a high number of wickets taken with the least number of balls bowled - rewarding strike bowlers.

    • Wickets quality
      Major 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
      Major 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 (< 25 total overs bowled). If the bowler has bowled less that 5 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.

    • Location
      This is a minor factor that adds a bonus to significant performances completed away from home.

    • Match status
      This factor rewards contributions made in significant matches like finals. World cup 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 5-wicket performances.

    • Rule changes
      ODI rule changes that generally favor batting such as fielding restrictions, power plays and duo new balls are taken into account by comparatively discounting past bowling performances.