The simple fact is that there is no such thing as a coin that is absolutely fair. Even a completely symmetrical coin could be biased towards one outcome - whether deliberately or otherwise – by the action of the person tossing the coin.
Some people’s technique will push the coin higher. Others might give the coin more rotation.
In a 2009 study, researchers at the University of British Columbia concluded that even a regular coin could easily be made to produce biased outcomes when the person tossing it was told “how to manipulate the toss of a coin” and incentivised to make it so.
Of 13 participants, each flipping the coin 300 times, all managed to produce more heads than tails. Overall, of the 3,900 tosses, 57% landed heads. One participant was able to obtain heads more than twice as often as tails.
Put to the test
In the haphazard and improvised spirit of backyard cricket, I decided to see how a cricket bat would land when flipped. I, of course, did not have access to one of the new Big Bash League bats so had to make to with the old battered bat from the back of the garden shed.
With a nod to procedural fairness, I decided to try two different techniques: low rotation (aiming for two of three flips while in the area) and a high rotation (as many flips as I could manage). Each of these techniques was applied 100 times to the bat being flipped from “hills” up in my hands, and 100 times from “flats” up.
I’ll be the first to admit that this resembles serious scientific rigour about as much as the browning patch of grass next to your parents’ Hills Hoist resembles the MCG.
A greater sample size would have been preferable, but this was as much as I could muster in fading light in a suburban backyard.
Based solely on the results of my backyard testing, you can likely chalk this one up as a win for conventional wisdom.
Especially when the bat was flipped with high rotation, it appeared to exhibit bias towards landing “hills”: 68 times from a “flats” up and 63 times for “hills” up position.
For the less vigorous flipping technique, its initial orientation influenced the outcome more and the results were closer to 50-50: the “hills” 58 times from a “flats” up and 48 times for “hills” up position.
In fairness to the league and its equipment suppliers, I would imagine that the bats used will be a little less prone to bias than the one available to me.
Nonetheless, whatever results Kookaburra’s testing machine produced with its bat, it is difficult to believe that a large, asymmetrical bat will be less susceptible to bias by the flipper’s technique than a simpler, smaller coin.
Finishing off the tail
Even if the bat flip is indeed not as unbiased as confidently claimed, it probably doesn’t matter. The decision to ditch the coin flip for its more unconventional counterpart is not one driven by a desire for sporting equity.
It’s a move designed to further distance the loud, brash, big-slogging and brightly dressed T20 league from traditionalists’ cricket, and to generate hype for the forthcoming season. With all of the international headlines that followed the surprising announcement, the decision already appears to be a huge success for Australian cricket.