A win for the ages, but it does not guarantee top 6
Still a long road ahead before Australia gets a top seed for the World Cup draw
Last weekend, I wrote a little tool to simulate World Rugby rankings based on user-defined outcome probabilities for a given fixture list.
I used it to look at what the rankings could look like for the World Cup draw, as discussed in this post.
One thing I built into the tool is that it is very easy to replace predictions by actual results and update the simulations. It does not mean that I will write about the update every week, but I think this week deserves it, for a number of reasons.
The first reason is that I want to be able to write this: the Wallabies came back from 22-0 down after 18 minutes, scored 38 answered points, and won at Ellis Park for the first time since 1963!
When I ran my initial simulations last week, I had given Australia a 6% chance of winning by more than 15 points, but this was to leave room for upsets. I felt it was generous.
The second one is that, combined with Argentina's heavy loss at home, it creates a big gap in the current rankings. The gap between Australia (6th) and Argentina goes from 0.03 before the weekend (82.08 vs 82.05) to 3.48 this afternoon (85.08 vs 81.60). There is now a bigger gap between the two countries than between Australia and England in 5th place.
The third one is that the impact of the range of outcomes for the rankings in December is a lot smaller, and the reason for it is quite interesting. Keeping all probabilities unchanged (apart from the two results from the weekend), Australia's top-6 frequency "only" jumps to about 65% (up from just under 52%).
Even if we hard-code two home wins against Argentina (to see what happens in that scenario), Australia still falls out of the top-6 about 20% of the time.
This is because some games for which the Wallabies could be considered favourites are now worth fewer points (as they move further away from Japan or Italy in the rankings) and for other games where they are still not favourites at this stage (New Zealand away, England, France, Ireland) they are now ranked close enough to lose more points in any defeat. Australia has gained unexpected points, but now also has more to lose. As a result, the distribution of their simulated ranking points is wider, but the median has not moved much (yet).
This half of the year is all about looking towards the World Cup. For the Wallabies, this win is great in terms of building momentum and confidence, but it is still too soon to be confident about having a good seeding for the draw.