Monday 29 September 2014

Average score is not par score

I've discussed cricket stats and betting in general a few times now. I'll get round to giving proper examples of the benefits and dangers of using them in due course but first a small but annoying example of the danger of bad stats.

I wasn't going to write about this for a while but one commentator's absurd assertion during Wednesday night's Glamorgan v Hampshire Twenty 20 match that "160 is always a par score" reignited my irritation on the issue.

So it's a bit of a gripe this one but it's good to get things off your chest - and there's also an important warning here for anyone new to cricket betting.

The issue is relevant to both innings runs and match odds markets and is seemingly cropping up ever more frequently in live televised cricket.

Even Sky Sports' pundits, usually vastly better than cricket board produced cheerleader commentaries where endless excuses for poor play suggest it must be a sackable offence to actually criticise a player, make this error.

Put simply: The average score at a ground is not the par score.

Average Score ≠ Par Score

The two words are not interchangeable. They mean different things. And mixing them up can cost you money.

Using the words interchangeably is a classic example of bad stats. And junk commentary. While the idea that "160 is always a par score" is just laughable nonsense.

The average score at a ground is exactly what it says. It is the average first innings score achieved at the ground.

The par score is day specific and can only be arrived at by taking all particular conditions relevant to that day's match into account.

Yet time after time when trading a cricket match you will hear something like "the average first innings score here is 161" followed 30 seconds later by "well, we know the par score here is 161 so...".

So why is this so dangerous and how can it cost the unwary money? A simple example explains it well:

It is entirely logical to expect more runs to be scored on a fresh "batting paradise" early season "road of a strip" to a dry, worn, 3rd use pitch  at the end of the season.

Say a ground has an average of 161 in Twenty 20 cricket. The range of scores that make up that average may well stretch from something like 114 to 203. Further examination of the stats might show that, in general, scores on 2nd and 3rd use strips are lower than first use pitches.

So if we're trading a game on a 3rd use worn pitch and viewers are being told the par score is simply the average score they are being misled. Especially if other on the day factors will have a run reducing impact too. Such as large boundaries, slow outfield and overcast conditions conducive to swing.

Now put this in a betting context. Bookmakers are not stupid. They will take more than simply the average score into account when setting a runs line.

Continuing our example let's say we are on that third use pitch and the most recent score on the pitch went pretty low with bats struggling. Boundaries are big, there is a strong bowling line up and overhead conditions are not bat friendly.

In these circumstances a bookmaker might set a line at 142.5. Commentators saying well the par score is 161 here will inadvertently mislead some into betting overs on the 142.5 line. On the face of it the low 142.5 line seems just too good to be true. And, of course, it is.

Now the overs bet may win or not. Doesn't matter. It is a bad bet. Make enough of these type of bets based on bad stats, incorrect assertions and bad commentary and, long-term, you will lose on them.

The irony is most commentators are ex-professional cricket players. They are well aware of the difference between average and par and would have regularly differentiated between the two in their playing days.

It's likely just laziness or lack of attention to detail leading to the misuse of the words.

Whatever the reason - don't let it cost you money.

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