Today I have been working on my research that is investigating if it is possible to predict the outcome of football matches. The measure I will eventually use, to see if the predictions can be considered successful, will include if it can make money at the bookmakers, if it it more successful than other tipsters etc.
One of the functions I have in my system is to be able to generate the league table for a given date. That is, taking into account the fixtures played to date, generate the league table for any point in the season.
I believe that my function is working correctly and today I was carrying out some tests to see if the league tables I generated were:
- Correct at the end of the season. That is, taking into account every match played, is my input data correct and does my algorithm process that data correctly.
- Does my algorithm, given a date, generate the correct table for that point in the season.
I initially thought that point 2 would be very time consuming to check but I found a very useful web site. http://www.statto.com is not only a very useful web site (for all sorts of reasons) but one of the facilities it offers is to generate a league table for a particular point in the season.
When doing my checks (and there are still a lot more to do), I have found some problems where my generated tables are not correct. This is almost certainly down to my inputting the results incorrectly, so I need to check all those.
However, my checks also highlighted another problem. Actually, I knew this was something that I needed to address but I had not really thought it through.
The problem arises when teams having points taken away. I knew that this happened and I had yet to include it in my system so I was expecting the tables not to match exactly.
However, I had assumed that the points were deducted at the start of the season but this does not seem to be the case. It appears that the points can be deducted at any time in the season.
This is not too much of an issue. It just makes the programming more complex than I had hoped.
The real issue is what do I do when a team has had points deducted?
Let me give you an example. A team has won 3 games and drawn 2. That means that they have received 11 points (you get 3 points for a win and 1 point or a draw). But, if they have had 10 points deducted then they will only have 1 point. This obviously affects their league position. If I am using the league position as one of the contributory factors in my predictive model, is this fair – or should I ignore the points deduction for the purposes of prediction?
On the other hand, their league position, with the points deduction, may affect the way they play, and could be a factor in the prediction.
I’m not quite sure what I am going to do yet.
The points deduction rarely happens, and as you state, when it does it is normally during the close season time. It is often common knowledge as to how many points the team are deducted before the start of the season, so any such deduction could be included before your prediction. Other points deductions are so few and far between I would suggest omitting them altogether.
That is exactly what I thought, but, last season Crystal Palace, Stockport, Darlington, Rotherham, Bournemouth and Luton (6 teams) all had points deducted.
Of those, 3 teams had them deducted at the start, 1 team had the points deducted at the end of the season and 2 teams had the points deducted during the season.
So, maybe it is not that significant but it's not that clear cut.
I agree, I wouldn't bother with the points deductions.
I would be more inclined to give extra bias for match winners missing the game through injury etc, it was clear last year that when Ronaldo didn't play for Utd they didn't do as well as expected, he was an exceptional player, but the same happens at clubs throughout the 92 clubs (I think that's how many are still in the 4 divs)
Do you have any provision of fixture congestion? Teams that are still playing in several cups often put out weaker teams against lesser opponents.