Impact Index is the only statistical system in cricket that measures every performance in a match relative to the other 21 performances in the same match (as there are 22 players in each match).
Therefore, every performance (be it in batting or bowling or even captaincy or wicketkeeping) is measured in the context of every game. This is done on a scale of 0 to 5 (up to 2 decimal points).
For example, Dhoni’s Batting IMPACT in the World Cup final was 5.59 in a match context, with wicketkeeping and captaincy impact also measured, it went up to 7.29 but in a career context, this is brought back to 5.
The system measures the performance in the context of the series or the tournament — and if it plays a big role (an IMPACT of 4 or more) in winning his team either, it gets further rewarded with a Series-Defining bonus (which is also a function of how the player has performed right through that series/tournament).
This way, Impact Index accounts for crunch performances – which is really the big picture in sporting achievement.
So, two players in the World Cup final got series-defining status – Dhoni and Gambhir, as both crossed 4 on the IMPACT scale – they got considerable IMPACT points on a career level).
This way, Impact Index is a largely objective measure of a player’s impact on the games he plays for his team. Every measure is done on the basis of the information contained within the scorecard (and nothing beyond).
Impact Index considerably improves on the conventional measures too. Like runs tally – here, it measures the proportion of runs a batting performance yields in relation to the runs made in the match.
Dhoni’s 91 runs got him a Runs Tally IMPACT of 3.64; in a more high-scoring match, the same runs would have lesser value and conversely more in a low-scoring match.
Strike rate – here, it measures how fast a batsman has scored in the context of the match (and therefore factors in the standards of its times).
In the World Cup Final, Jayawardene, who got 103 in 88 balls, registered a Strike Rate IMPACT of 0.95 whereas Dhoni who got 91 in 79 balls got a Strike Rate IMPACT of 0.80.
Batting functions also include the impact of chasing and how much pressure a batsman absorbs in the middle – the latter based only on the basis of falling wickets and nothing more.
Dhoni got 0.66 as Chasing IMPACT and Gambhir 0.70. Moreover, for handling the situation at 31-2, Gambhir also registered Pressure IMPACT of 0.64, as did Kohli.
Wickets tally – here, the system separates the lower-order wickets from the rest. Economy IMPACT – here, it measures how many runs the bowler has given in the context of the standards of the match.
In the World Cup final, Malinga had a economy rate of 4.66 whereas the match standard was 5.58, so he had an Economy IMPACT of 0.34.
The system also measures elements hitherto found impossible – like pressure a bowler causes on the opposition (when he takes successive wickets that kicks in mathematical pressure on the opposition) or the ability of a bowler to break partnerships (based on the standards of the match) and so on.
In the World Cup final, when Perera got Gambhir and Dilshan got Kohli, they both respectively registered a Partnership Breaking IMPACT of 0.12 each.
In the end, Impact Index neatly compresses all cricketing parameters in a number between 0 and 5. Rather than being simplistic and subjective, it is more accurate than anything that has ever existed before, and also much easier to comprehend than anything in the game previously.
The FAQs section clarifies more.