Algorithmically predicting the results of the 2019 Rugby World Cup

I've been working on a rugby prediction algorithm for a while now. My basic premise is that the World Rugby rankings are a good indicator of past performance, but don't give the full picture when predicting future results. I've already visualised my predictions based on form alone, and the results look reasonable - so is there room for improvement?

My hypothesis is that a more accurate prediction can be made if we take into account short-term form and past performance against specific opponents.

With this in mind, my new model combines four key metrics:

1. All-time performance - as shown by current world ranking
2. Recent Form: tier 1 - how well have the team performed in their last 10 matches against tier 1 opposition.
3. Recent Form: tier 2 - how well have the team performed in their last 10 matches against tier 2 opposition.
4. History against opponent - how well have the team performed against the specific opponent we're predicting the result for?

There's obviously plenty more that I can add to this algorithm, but with the World Cup actually starting soon (tomorrow, at time of writing), I've got a hard deadline for "just shipping" whatever I've got.

The predictions