Going into 2022, India were 16 points ahead of Australia on the ICC Test rankings table, 124 to 108. Less than three weeks later, that lead has vanished as Australia swept to the top of the table with 119 points, pushing India (116) down to third place. Obviously, this is because there were two series that concluded in this period - Australia beat England 4-0 while India lost to South Africa 2-1 - but if you are looking for more on the hows and whys of this shift in rankings, here are a few points which should help.
Away wins don't fetch extra points
The period considered for the current rankings is from April 1, 2018, with the matches till March 31, 2020 getting 50% weightage, and the games after that getting full value. In this entire period, Australia played a mere seven Tests overseas (two wins, three losses), compared to 20 at home. India, on the other hand, played 25 away Tests, achieving a 10-12 win-loss record.
However, away wins don't fetch extra points in the rankings. So Australia's 13-4 win-loss record in their 20 home Tests counts for plenty. India had two series wins in Australia during this period, but they count for no more than they would have had India won those series at home.
This is an aspect of the methodology that urgently needs fixing, given how much more dominant each team is at home. India had a 12-1 record at home in this period, and 10-12 away; New Zealand were 11-1 at home and 5-6 away. Because of the way the rankings work, Australia benefitted.
In terms of overall win-loss record in this period, Australia were 15-7, compared to New Zealand's 16-7 and India's 22-13. In the period since April 1, 2020, when the results have a 100% weightage, New Zealand are 7-2, Australia 5-2, and India 9-6. It's undeniable that Australia's overall stats are impressive during this period.
Quality of the opposition matters
The home-away factor doesn't count for anything, but the quality of the opposition does make a difference. Beating a team ranked higher counts for much more than beating a lower-ranked team. Conversely, losing to a lower-ranked opposition significantly dents a team's tally.
For example, when the Ashes started, Australia had a one-point lead over England (108 to 107). Going by the team ratings the series should have been close, but since Australia won so convincingly, they gained 11 points while England lost six. Australia gained more than England lost because they had played far fewer matches in this period; with a lower base, the changes are more volatile than with a larger base.
On the other hand, going into the South Africa tour, India were on 124 points compared to South Africa's 88. That meant India were overwhelming favourites to win the series: according to the way the calculations work, they would have needed to win 2-0 just to maintain their pre-series rating of 124 points. There again, not considering the home-away factor means there is no recognition of the fact that South Africa are much tougher opponents at home than away, just as India are not as formidable overseas as they are at home.
The 2-1 series defeat meant India lost eight rating points while South Africa gained 11.
India's 2-1 lead in England doesn't count
The Test rating calculations are done only at the end of a series, so everything that India did in wresting a 2-1 lead in the four Tests they played in England doesn't count towards the rating points. They will be added after the fifth Test of the series is played later this year.
However, even if that series was taken as a completed one with India winning 2-1, they would still have climbed up only to 118 rating points, while Australia would have stayed ahead on 119. The gap would have narrowed, but Australia would still be the top-ranked Test team in the world today.
Their grip on that position is a tenuous one, though, and Pat Cummins and his team will be tested thoroughly in terms of their overseas skills, with tours to Pakistan, Sri Lanka and India lined up over the next 12 months.