Sunday, December 31, 2006

2007, Nottingham Forest, top of the table...

2007 begins for Oldham Athletic with the visit of Nottingham Forest. What has been an unexpectedly successful season would enter a new stage with victory, which would propel Latics into the automatic promotion positions for the first time all season, and the first time at such an advanced stage of the season since Iain Dowie's expensively assembled side managed it in around 2002. Three consecutive victories, each achieved with the scoring of three goals, have given Latics sight of automatic promotion spots. Victory over Forest earlier in the season provided the catalyst for the run of form which has seen Latics rise from bottom of the table to very near the top. Can another win begin a spell of the season in the promotion places?

Forecasting the attendance in this match is tough. The previous two home matches are not a very good guide, not least because they were before Christmas, not least because they were before two excellent away victories which surely must fuel belief amongst the people of Oldham that the team can do things this season, not least because the visit is of Nottingham Forest, by some distance the biggest team in the division, and not least because it's New Years Day.

My model gives a prediction not a million miles out from what I'd expect: 8,401. Enough people (like me!) should be still around the North West who haven't yet gone home, to help the gate display holiday season effects, as well as the visit of a huge and successful team, on the back of a monster run of form that could result in Oldham topping the league table by 5pm.

Come on Oldham!

Thursday, December 14, 2006

Another interesting challenge...

...Oldham Athletic will be charging just £2 for adults, and £1 for kids in their next two home matches. These are matches against Brighton and Hove Albion, and Northampton Town, matches which otherwise would not attract a very high attendance at all. It's a great idea, I'm totally for it - get a full house in, hopefully get some kids hooked on Latics, especially if the team can carry on playing as they have recently (unbeaten in nine league home matches, seven wins).

But it creates havoc for modelling and forecasting. On the other hand, it's a known break. One of the biggest problems with forecasting is structural breaks, if the break affects the mean of the time series being forecast. Before the break, it's generally quite hard to predict one will happen, and then if it can be predicted, the size is another matter entirely. If a break happens, next period when forecasting, one needs to know whether this is simply an outlier, measurement error, or an actual break.

So here, I have quite a lot of information: I know something will happen that can only be described as a break - the two previous big discount matches (Grimsby (free) and Torquay (fiver)) have attracted substantially larger attendances. I further know it will only last for two matches, it is not permanent, but it's not a one-off either. And I'll know the reason why the break has occured.

All in all, it makes for an interesting experiment. Will the attendances be as large as the Grimsby or Torquay matches? A method for capturing a break is to add a dummy variable estimated over some observations in the sample, and extend this dummy into the forecast period. Usually in time-series, the dummy is for the last few observations. However, here as we have some idea from these matches how big the break might be, it makes sense to use this information.

Extending the Grimsby dummy gives a forecast of 11,670, and extending the Torquay dummy just 6,856. I think somewhere inbetween these two examples is more likely. A combination, weighting Grimsby at 0.6 since £2 is closer to £0 than £5 gives a forecast of 9,442, but I think a higher weight should be used, since zero prices have wierd effects. A weight of 0.75 on Grimsby provides a forecast of 10,230, which pleases me.

Come on Oldham!

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Tuesday, December 05, 2006

Attendance vs Crewe

It's been a couple of weeks since the last home match, and with a couple more wins under the belt, one might expect a bumper gate in the home match tonight against Crewe, which kicked off about seven minutes ago. Particularly given one of the two wins was a crushing 3-0 win at local rivals Huddersfield. However, my model of attendances predicts a gate as low as 4,289.

A number of factors cause this: it's a Tuesday night; it's December, Christmas is coming and all that. However, it's the first home game for a while.

I can't believe the gate will be that low. I'm looking into forecasting using what is apparently a very good forecasting device, the exponentially weighted moving average. By altering the parameter on the weight from 0.1 to 0.9 I get a range of forecasts between 5,122 and 5,903.

I'm inclined to go with the naive forecast with parameter 0.1 to be honest, I reckon the gate will be just around 5,000. I could be proved wrong, and my model right however. I just hope Latics win!

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