BBL Elo – Ratings and Win Chances

Since this is an important thing, I’ve stuck it to the front page, right at the top. This will stay here from its publication date, October 18, to sometime near the end of the Big Bash League, probably in early February. Think of it like FiveThirtyEight’s interactives. -Nick

If you want to just see the ratings and win chances, without reading about what’s behind it, then go to this link: Otherwise, read on!

I’ve been plugging my BBL Elo ratings for a while now.

And now, I’m ready to unleash what I think is the best part of it upon the world.

As part of the calculations for Elo, it provides an estimated winning probability. This is part of it: you get more points for winning if you have a 40% chance than you do if you have a 60% chance.

This estimated winning probability, however, is useful in that it can be used for predictions.

That’s what I’ve done here.

I’ve put all 28 possible BBL matchups into the formula, and used it to work out how likely each team is to win:

BBL win chances.png

(I know it might not look like there’s much variety, but that’s because the teams have regressed to the 1500 mean at the end of the 2015-16 season, which Elo does. If you take the highest Elo rating in BBL history (1583, by the Perth Scorchers after the 2014-15 final) and match it up against the lowest (1389, by the Sydney Thunder after losing their 20th game in a row to Hobart), then Perth has a 75.34% chance of victory, pretty good in a two-horse race.)

The 8-0 and 0-8 record chances are based on each team’s fixture. In particular, the only variety are their Elo ratings, and the teams that they play twice. The Adelaide Strikers and the Melbourne Stars have the same Elo rating, but Adelaide plays the Hobart Hurricanes twice, but the Melbourne Stars play the Renegades twice. The Renegades are harder opposition than the Hurricanes, so that contributes for Adelaide.

And that also leads in to something that you might have seen before…

output_9nt3n4Yes, it’s that graph from earlier! Even if it’s at the bottom of the file extension trustworthiness ladder, you can trust this one. It’s from me, with reliable information.

Let’s look under the hood a little, at the Melbourne Renegades in particular, because they’re the team I support. (Don’t like this? Write your own blog post.)

under the hood.png

(I have too many tabs open. Sue me.)

Now, an explained diagram of it all.

under the hood explained.png

And if you want a little more indepth information on how the chances are calculated, it’s right here.

colour coded explanation.png

Because I didn’t want to upload a similar spreadsheet every time a BBL game was played, I decided that I would throw them on Google Drive, free for everyone to view, where I could update it as the season went on. If you want, I think you might be able to download them and have a playaround yourself.

The link, if you missed it:


Thanks to @ThatDMack for pointing out a terrible mistake.

Cool Stuff People Did

October 18


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