How'm I doin' so far? - Part 3

Asleep at the wheel

After reaching dizzying heights of up £16.57 from £1 bets something strange happened. After Easter some teams who were safe from relegation but no chance of playoff/Europe spots just stopped showing up.

It makes perfect sense when you think about it, but when you’re a computer algorithm that hasn’t been trained to know about such “sleepwalking to the end of the season” it takes you by surprise. The model thought these teams would play as well as they should do whereas the human punters I’m competing against knew better. The model thought is saw value where there was none and plummeted to only £1.30 up.

What’s that done to the graph?

A rapid decline.

I’m faring better with the start of the new season and have climbed back to currently £4.80 up.

Lessons Learned

When building the model I was aware of some cases where a team would not perform as well as past data would suggest, notably newly promoted teams go from being the best in their league to one of the worst. I accounted for this by introducing a different-division factor, which was essentially a value between -1 and 1 showing what proportion of past games used by the model were played in a different division, with negative being in a lower division and positive in a higher one. 0 means all sampled games were in the same division.

This variable alone made a significant improvement in the accuracy of my model. I should have applied this logic to games remaining in the division, and what they had to play for.

It seems fairly consistent how many points are needed for safety and playoff positions year by year, were I to retraining the model I would this time calculate how many games each team had remaining, how many points they had, and how many they were off/above playoff/safety as this should help protect against this false value.

Either that or I’d just turn the Pi off after Easter

Re-train?

I’d like to retrain the model with new variables at some point but regrettably it won’t be soon. I’m currently working on Ice Hockey analysis which I hope to start publishing in a different platform soon, but it would be nice if I can get the new model up and running by Easter. In either case I’ll keep this current model going as long as I can stop the scraping scripts from falling-over for.