Roulette Wheel BiasChances are you know what bias is; to show prejudice or inclination towards one thing/group/person over another. We all know a pushy parent who thinks their child is brighter than everyone else’s right? A perfect example of bias.

When it comes to roulette though, and more specifically the roulette wheel, bias becomes much more important.

For a roulette wheel to show bias means that it is more likely for the ball to land in one area than another, and in a game that is supposed to be totally random and fair, this is a problem. Unless of course you know how to spot and exploit that bias, which many gamblers have done in the past.

Wheel bias then, is a roulette wheel which is not perfect, not truly random, and favours one area or set of numbers more than the others.

What Causes Roulette Wheel Bias

Worn Roulette Wheel

Credit: John Wardell Flickr

It is much less common and less likely now than it used to be, as wheel designs have improved and casinos have become more adept at testing their wheels, but wheel bias is usually caused by wear and tear or minor defaults in the wheel.

A roulette wheel is designed so that it is impossible to figure out where the ball is going to land until the very last second, and even then it can be tricky. Plus, no more bets will have been called well before this point in time, so even if you could predict the outcome just before the ball came to rest you couldn’t bet on it anyway.

However, over thousands of spins the ball can slowly wear down the frets for example, or a fret can become very slightly loose, and this all has an impact on where the ball lands. Depending on the design, the spinning mechanism could become ever so slightly loose, which will again cause the wheel to be slightly biased.

The result is that the ball will stand more chance of landing in certain areas of the wheel than others. It wouldn’t be so obvious as to land on the exact same number every time, but over a great number of spins the statistics would show a bias towards a certain set of numbers grouped together.

Wheels used to be made differently and less robust materials such as wood were included in key elements of the design, so the potential for parts to become damaged or worn down was greater. These days, while polished wood is still used for the frame to make the wheel look beautiful, materials like metal are used for the dividers and pockets, as this will not wear down so easily.

Is it Easy to Spot Wheel Bias?

Man Watching Roulette WheelWhen people talk about spotting wheel bias it is slightly misleading, because it’s not something you can really see. If it was, the casinos would spot it too and fix the issue.

Everyone who has been successful in exploiting roulette wheel bias has done so by meticulously watching and recording the results of thousands of spins.

The first person thought to have done this was Joseph Jagger back in the 1880s, and even he managed it by hiring helpers to watch all of the wheels in the casino and write down the results. So he didn’t ‘spot’ wheel bias, he used data to discover it and then bet on the biased wheel based on that data.

So in some ways spotting wheel bias is easy, because data doesn’t lie, but the effort it takes to collect and analyse that data is substantial, and these days, also fairly pointless. And good luck not getting thrown out if a casino catches you recording the results. Even if you did do all of this, to then go and bet your own money on the wheel you think is biased, and to take the losses that will invariably come along the way, takes nerves of steel.