The ICC Player Rankings are a sophisticated moving average. Players are rated on a scale of 0 to 1000 points. If a player’s performance is improving on his past record, his points increase; if his performance is declining his points will go down.
The value of each player’s performance within a match is calculated using an algorithm, a series of calculations (all pre-programmed) based on various circumstances in the match.
All of the calculations are carried out using pre-programmed formulae, using the information published in a Test match scorecard. There is no human intervention in this calculation process, and no subjective assessment is made.
For a batsman, the factors are:
For a bowler, the factors are:
Bowlers who do not bowl in a high-scoring innings are penalized.
The players’ ratings are calculated by combining their weighted performance in the latest match with their previous rating. This new ‘weighted average’ is then converted into points. Recent performances have more impact on a player’s rating than those earlier in his career, but all his performances are taken into account. A great player who has had a lean run of form will still have a respectable rating.
Players who miss a Test match for their country, for whatever reason, lose one per cent of their points.
New players start at zero points, and need to establish themselves before they get full ratings. There is a scale for calculating qualifications. For example, a batsman who has played 10 Test innings gets 70 per cent of his rating (i.e. his rating will be between 0 and 700 points). He doesn’t get 100 per cent until he has played 40 Test innings. A bowler who has taken 30 wickets also gets 70 per cent of his full rating. He doesn’t get 100 per cent until he has taken 100 Test wickets. This means that successful new players can enter the top 30 after just a few Tests, but are unlikely to reach the world top five until they have many Test matches under their belts.
The principles behind the ODI Ratings are similar to those for the Test Ratings, with the following important differences:
The Women’s ODI Rankings operate in the same way as the men’s equivalent. However, statistically there are some differences between men’s and women’s ODI cricket, so there are some adaptations for the women’s version. The average scores in women's ODIs tend to be lower than in men's so the points scales were adjusted so as not to favour bowlers, and there are fewer women play ODIs in a given year than men, so there are typically more men bunched within a few points of each other in the table than in the women's equivalent.