Just a quick update this time, as I am travelling. To recap round 2:
Again, not too bad. The model really only got one result badly wrong – Japan vs. Scotland, where it had picked a Japan win (albeit narrow). This highlights one of the downsides of this type of analysis – we do not really have that much data to go on for some teams, and so single results can have a big impact. Remember we are only using results from the past 2 seasons – going further back in time gives us more data to work with, but runs the risk of said data being out of date and not reflective of the teams’ rating now. We also picked the England-Wales game incorrectly, although that was always going to be close. The key difference (or so the model thought) should have been the home advantage to England – as it turned out, it may have been a disadvantage on the day…
Round 3 ratings and picks
The model has updated the ratings based on the results from round 2 (remember, RWC games count double):
The big changes are largely with the minnows shifting up or down depending on whether they lost by more or less than the model predicted in round 2. Scotland have improved by 4 points, although the model does not think this will be enough to save them against South Africa (see below). Japan drops by 9 – again, this is due to the limited data (number of games) to base the ratings on, which adds a certain amount of volatility. Interestingly, Argentina is continuing to improve, and is now rated just shy of Australia, England and Wales.
So, for the upcoming Round 3 games, the model’s picks are:
So, according to the model, the key games to watch are Samoa vs. Japan, and England vs. Australia. Again, the points difference for England is coming from the home advantage rating, suggesting a very close match is in store. Wales vs. Fiji may also be closer than the model suggests – it of course does not take account of injuries affecting a team’s rating.
Let’s see next week how things have gone!