Greater Western Sydney, by general consensus, are the favourites to take the 2017 AFL premiership, but don't be fooled into thinking they have the season stitched up just yet. In fact, Elo ratings suggest the Giants only have the fourth-highest probability of making the finals, behind the Swans, Crows, and Bulldogs.

Our estimates of teams' chances of making the finals are based on Elo ratings, which are a popular way of rating sports teams. In an Elo ratings system, teams are rated based on their match results, after taking into account home-ground advantage and the quality of their opposition.

We use these ratings to predict future matches, then simulate the season 10,000 times to calculate each club's chances of ending up at each position on the ladder. These projections take into account the quality of the team at the end of 2016 and the difficulty of their schedule in the coming season.

While the Giants are heavy favourites with bookies, experts and fans alike, our projections suggest there is hope for Leon Cameron's rivals. In fact, our projection of the 2017 season makes it clear that almost every team has a meaningful shot at playing September football this year.

The Swans sit in pole position, with a 53.9 percent chance of a top-four finish to the regular season, but five other teams also have a better than one-in-three shot at the top four. Virtually every club besides the lamentable Lions have a meaningful chance of making finals. Essendon only have a relatively slim one-in-15 (6.6 percent) chance, but that might be understated for reasons we'll get to in a moment.

Perhaps the key insight from simulating each team's finals chances is the level of uncertainty about the coming season. Even the most fancied teams have a 20-25 percent chance of missing the finals, because of the possibility of bad luck with injuries or just because they turn out to be worse than expected.

The limitations of Elo

Elo ratings are fairly simple - they only take into account teams' past performances, adjusted for home-ground advantage and the quality of their opposition. But they're powerful - match predictions from Elo ratings are pretty accurate. They tend to get more accurate as the season goes on, as the ratings system learns about the quality of the teams. As such, we will be updating our ratings on a monthly basis throughout the season.

At the start of the year, Elo ratings are less accurate as a measure of teams' true strength. Pre-season Elo ratings really just reflect how good teams were last year, with an across-the-board adjustment to bring the good teams down to earth and lift the bad teams back up towards average. The ratings don't take into account changes in personnel in the off season.