Wednesday, May 16, 2007

Ripsometrics revisited

The second annual Rock-Paper-Scissors tournament took place in Las Vegas recently. According to the New York Times, it was a big event. Bud Light was the sponsor, and ESPN was there.

It seems like the game should be just luck. Predictably, adherents disagree:

Some view the game as a matter of pure luck, but others, like [league founder] Mr. [Matti] Leshem, say there is a clear-cut strategy that involves learning to read an opponent, much as poker players do.

“It’s a sport that ... if you really want to get good at, you can.”

It would be interesting to check, if only the sport had a Retrosheet. There were no repeat winners in the last five years of the World Championship in Toronto; but the winner of an impromptu tournament a while ago was famed poker player Annie Duke.

I'm extremely skeptical. In any case, you can always give yourself an equal chance against even the most skilled opponent by choosing your play randomly.

Hat tip:
Freakonomics blog.


At Wednesday, May 16, 2007 9:45:00 AM, Anonymous Anonymous said...

I like cats

At Wednesday, May 16, 2007 12:45:00 PM, Anonymous Anonymous said...

Of course, you can guarantee breakeven results, but if you can't exploit the exploitable you will be below average in a field.

At Wednesday, May 16, 2007 12:48:00 PM, Blogger Phil Birnbaum said...

Agreed. But if all competitors have perfect information about the skill level of all other competitors, the inferior player will *always* pursue the breakeven strategy, and everyone will have an expectation of .500.

You can only benefit from skill if the other players don't know you have it.

At Wednesday, May 16, 2007 3:53:00 PM, Blogger Unknown said...

There is also a question as to whether you can play randomly. Good players may be able to id giveaway signs that a player will throw a rock , or paper ....

At Wednesday, May 16, 2007 3:55:00 PM, Blogger Phil Birnbaum said...

Oh, yeah, there might be tells. Never thought of that!

At Wednesday, May 16, 2007 9:46:00 PM, Anonymous Anonymous said...

It may also be harder than we think to maintain a truly random strategy in the face of apparent patterns by your opponents. Or even your own previous plays. I bet most people, if told to play "randomly," would alternate plays more regularly than would happen in a true random pattern (for example, rarely using the same play 3 consecutive times). Think about it: playing totally randomly would not be easy.

At Thursday, May 31, 2007 12:51:00 PM, Blogger Matt said...

By the way, playing "randomly" is exactly what Annie Duke did on the way to winning the impromptu RPS contest at the 2005 WSOP. She held a dollar bill and read the first digit of the serial number: 1-3 Rock 4-6 Paper 7-9 Scissors (0 meant read the next number). She read a different digit for each round and so was random.


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