A note on the database

Whilst the database is giving more clarity on the effectiveness of attacking performances there are a range of improvements that are in the pipeline to make it more accurate. These are laid out below; some are quick and easy and will be introduced relatively soon – the only thing stopping them being done immediately is time. I’m looking for a gap in the schedule where I can make a number of changes at once rather than drip them in piecemeal. Other changes are more substantial and it may be post Championship before I can get the space to ensure they are accurate.

Currently there are only two determinants taken into effect – where the shot was taken from and was it from play or from a deadball. These are providing large differentials, so are proving very useful, however there a number of other obvious determinants; weather, was the player under pressure when shooting, in closer to goal was the shot at goal or for a point etc.

Weather – this is hard to judge. Generally players seem to have more trouble with wind than rain – but how to measure the extent of the wind from the couch? I think we will have to bear this in mind when reviewing certain games but putting a value on it might prove to be too judgemental.

Pressure – I did track whether a player was under pressure taking a shot during 2010 (and continue to do so in 2012) however it can be very difficult to ensure consistency through different games and camera angles. I’d be happy that as I’m the only one doing all the games there would be a high level of consistency however I’m reticent to apply the change until I’ve time to thoroughly check it.

Goal chances – a big weakness of the database so far is that if a player takes a shot at goal he gets the same result whether he gets a goal or a point. This is obviously wrong and I will be looking to amend the expected returns for shots on goal in the coming weeks.

Treating all deadballs the same – linking into the above a penalty is treated the same as a free in section 8. Similarly a 45m from in front of the posts is treated the same as a free just outside the 21m line from in front of the posts. One of the first changes I will be doing is to change the expected returns for 45s from other frees – penalties and shots from the sideline may have to wait until I have more data. In 2010 there were only 7 penalties & 15 shots from sidelines charted.

The state of the game – is it a blowout lead (thus less pressure on the shot)? Is there a difference between shots in the first 10 minutes and the last 10? These effects can be measured but it will probably be after the Championship before this can be accurately modelled


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