Wednesday 26 June 2019

World Cup simulation update - 26 June

Are the wheels falling off?

England have now got a 4 win, 3 loss record, and, with 2 difficult matches coming up, have a genuine chance of not going through to the semi-finals. They are still not relying on other results, but they're getting close to the point where they are.

There's been a significant change, with Australia going up, and England going down. England are now expected to get to 10 points. That might still be enough. But it also might not be.
England's ranking has now dropped well below India's, to the point where the expected probability of England winning against India has dropped by almost 10%. They're still ahead due to home advantage, but the difference is decreasing.
There's about a 15% chance that a tie-breaker (total wins or net run rate) will be required. This may count out Sri Lanka, who have had two rain affected matches, and so will probably be on fewer wins than anyone else with the same number of points.

We see a huge drop in the semi-final probability of England, and a resultant increase in Bangladesh, Pakistan and Sri Lanka. Australia have qualified now, and there are fewer options now for New Zealand to be knocked out also (only 35 out of 50000 trials saw New Zealand miss the semi-finals.)

The decrease in England, and increase in probability of lower ranked teams making the semi-finals has meant that there are a lot more semi-final combinations with more than a 0.5% chance of happening. West Indies vs New Zealand was an epic match in the pool play, and that's now a reasonable possibility for a semi-final. The ICC and Star Sports will be licking their lips at the prospect of the 8th most likely outcome - an India Pakistan semi-final would be absolute ratings gold.
This is the first time that England has dipped below India on the winning probability graph, but it's hard to win the final if you don't get out of the group stage.

Monday 24 June 2019

World Cup Simulation update 24th June

 Here's the update after the South Africa vs Pakistan match

Firstly, this pushed Pakistan's ranking back above Bangladesh's ranking, although they are both so close that the match between them is now predicted as 50.2% to 49.8%.
 Looking at the expected points, Pakistan have now jumped ahead of Sri Lanka and Bangladesh.

It's looking fairly likely that 5th place will be on 9 or 10 points, while 4th will be on 10, 11 or 12 points.

My simulation only uses net run rate as the tie breaker. Accordingly, there's actually a slightly higher probability of Sri Lanka and Pakistan getting through than this shows, and a slightly lower chance of England and Bangladesh.

It's takes a lot of processor time to improve the simulation, and it's likely to be less than 1% difference, but I might have a go at improving it once we get to the last 5 matches.

England are still the overwhelming favourite to be the 4th team to go through. There were still 41 out of the 50000 trials where New Zealand hadn't made it. So nobody is guaranteed through just yet.

If you have semi-final tickets - this is who you're likely to see.

The probabilities for Bangladesh and Pakistan being so low here are understandable. They both have about a 5% chance of making the semi-final, but, given that they both have about a 1/3 chance of winning each match against the top teams, it gives them a roughly 0.5% chance of winning the tournament from here. However, if Bangladesh, Australia and Pakistan win the next 3 matches, that number will rise.

It's starting to look like England's style that is so effective in series may not be so effective in one off matches. It will be interesting to see if that trend continues.

Sunday 23 June 2019

World Cup Simulation Update, 23 June

Here's the latest outputs from the simulation.

England's loss to Sri Lanka opened the door somewhat, but we can still be fairly confident in who the semi-finalists are.
 England's ranking has gone down, after two losses to fairly ordinary sides.
It's looking like 10 points will be the magic number. Roughly a 10% chance that we'll rely on a tie-breaker.

The average points expected certainly favour England on that count to be in fourth

Accordingly, they have a much higher chance of making it through.

What the likely match ups are. (Teams in alphabetical order, rather than placings)

England are still firm favourites by my model. Home advantage is massive.

Monday 17 June 2019

World Cup simulation update

The group stage of the World Cup is now roughly half way through, and there are 4 clear favourites to be the semi-finalists.

Afghanistan is the first team to be eliminated (they may have a mathematical possibility, but they don't have a statistical one). At this point, Sri Lanka are not far behind.

The rankings of the teams have remained fairly consistent, suggesting that the extra weighting for world cup matches is about right.
The fact that almost all the teams seem to have gone up is due to them all being relative to Afghanistan. Afghanistan do not seem to be quite as good as they were seeming to be and so they have dropped, but as they are set to 0, it's pushed everyone else up slightly.

The semi-final probability is the most interesting. 

I personally feel that this is underestimating the chances of South Africa, but we will see as the tournament progresses.

The key point on this graph is match 5, where Bangladesh overcame South Africa. If South Africa had won that match, they would be on about 40% and New Zealand and Australia would both be a lot lower.

The simulation also puts out the points for 4th, 5th and the difference between them. This suggests at the moment that there's only a fairly low chance that net run rate will come into play. However, one more rained out match, or a Bangladesh upset of Australia, and this could change dramatically. This makes the expected lines to be 9 points for 5th place, and 11 points for 4th place.

So far of the teams that I've had as favourite to win, 14 out of the 17 have won. Given the probabilities that the models assigned them, that's slightly higher than I would have expected - I would have expected there to have been 4 upsets rather than 3, but it's still telling me that my model is working quite well. That may be due to teams not always playing their best combinations in every match between the world cup, adding extra uncertainty to the results than exist inside a world cup.

It will be interesting to see if it continues to have the same success rate after the cup is finished.

Finally, applying the same system to find the probable winner gets the following results:
England are still favourites, but India are not far behind them.

Sunday 16 June 2019

India vs Pakistan statistical preview.

Here's a couple of little charts etc for today's match up

This suggests that 250 would be a quite defendable total. The par score here is much, much lower than on most grounds in England.

The ground is actually fairly well balanced between both pace and bat and spin and bat - but still favouring both types of bowler slightly.

Old Trafford is the black spot, the grey points are other grounds around the world. Spin and pace friendliness are calculated based on the success of different types of bowlers on those grounds, taking into account runs conceded, balls bowled as wickets taken.

Adding to the ground data all the matches where India has batted first and all the matches where Pakistan has batted second, brings this graph:

This suggests that, taking into account the teams, that a more normal curve applies. If India score under 200 they're unlikely to win, 250 is the 50/50 point and 300 is more like a 75% chance of defending.

Thursday 6 June 2019

World cup simulation update

Just before the World Cup started I wrote a post about a simulation that I had written to find the teams chances of making the semi-finals and chances of winning.

I've spent quite a bit of time improving it over the past week or so, learning some new machine learning techniques to improve my rankings etc.

Below are 3 graphs that show the change in rankings, semi-final probability and win likelihood.

These rankings are all relative to Afghanistan (who are first in the alphabet) Afghanistan will always be on 0. Every other team will change around them. any team ranked lower than them will get a negative rating.
The new model gave New Zealand and South Africa lower chances of making it, and Bangladesh and Australia higher chances of making it. South Africa have dropped lower still, while West Indies and Bangladesh have made up ground.

New Zealand has moved ahead of South Africa into the 4th most likely to win, but both teams are still at fairly long odds.

Monday 3 June 2019

Preview - Match 6 - England vs Pakistan - Trent Bridge

England and Pakistan return to the scene of a recent run-fest, but this time there is more on the line.

To say that Trent Bridge tends to be batting friendly is like saying that Elton John tends to play the piano. However, the pitches so far have not exactly been typical of the grounds, and this may prove to be another incident of that.

England start as heavy favourites - Bet365 have them at 82%, Google gives them a 79% chance of winning, and my model gives them 84%. But the favourites don't always win ODI matches.

Here's the historical first innings score chart:

Pakistan have a reputation as an unpredictable team, but the reality is that they are one of the more predictable sides. They very rarely beat teams that are better than them, and very rarely lose to teams that they are better than. England should win this one reasonably comfortably.

Sunday 2 June 2019

Preview - World Cup group match 5 - South Africa vs Bangladesh - The Oval

Today Bangladesh get their campaign underway, and South Africa get a chance to bounce back from their early loss.

This is predicted to be a win for South Africa, but I think the betting market are overstating the difference between the teams. Most of the bookies have an implied chance of winning of about 76% for South Africa, but my early model had them at 67%, and after their loss to England and Bangladesh's recent series win over West Indies (which looks more impressive now that West Indies have turned out to be quite good), the gap has shortened to 66.6% for South Africa vs 33.4% for Bangladesh.

The Oval pitch is one where there has been variety of conditions recently, so it's hard to know what a good score is until both teams have batted. Here's the historical graph:

The numbers have all dropped down by 2 or 3 runs as a result of the last match. 

One thing that does not play to Bangladesh's advantage here is the pitch. This is probably the bounciest pitch in England, and is more like a South African pitch than a typical English pitch. Bangladesh, however, play on probably the lowest, slowest pitches in the world.

If this match was at Taunton or Old Trafford, then Bangladesh may well be favourites. But not at the Oval. I'd expect South Africa to do well here. If they don't, then the semi-finals suddenly look a very long way away indeed.

Saturday 1 June 2019

Preview - World Cup group match 3 - New Zealand vs Sri Lanka

This match is at Sophia Gardens in Cardiff. It's likely to be cool and damp, but with no rain. That's likely to play into New Zealand's hands.

New Zealand are distinct favourites - Bet365 have them at 78%, Google has them at 79%, and my model has New Zealand at 81%. However, none of those are at 100%, and the match isn't played on paper - Sri Lanka are still capable of pulling out a big performance.

Sophia Gardens is an odd shape, similar to Eden Park in Auckland, so it's a shape that New Zealand should be comfortable with. However, New Zealand has a mixed record at the ground - it was host to the match where New Zealand famously lost to Bangladesh in the Champions Trophy. In the one previous match between the two sides there, New Zealand won by 1 wicket, only just managing to win despite bowling Sri Lanka out for 138.

Teams batting first have generally not done well at Sophia Gardens unless they get a very big score. It's likely that both teams will want to chase here.

Again a score of 290 would be below par based on historical data, but ICC events sometimes have the pitches in different conditions to normal matches, so there's a chance that a lower score might still be very competitive.

As with some of the other matches, one of the more interesting things here will be the selections. What combination of players will each team go for?

Whichever way it goes - matches at Cardiff have tended to be interesting, even when the teams have seemed to be mismatched on paper before hand, so this could be the first match that's actually interesting on the field as well as just in the lead up.