Sunday, June 03, 2007

A Hidden Problem with Sharkscope?

As I've mentioned in previous posts, I'm less than enamored about a lot of the products that are available to help get a picture of one's opponents in a less-than-noble way, that being by direct play at the tables. Sharkscope is one of those products, though it's probably at the minor end of the scale, certainly not as offensive to a purist as a PokerHUD or a Pokerbility or other products which try to create an artificial 'live time' advantage for the player.

I made a deep run in the $20K on / Carbon Poker a week ago, and in one of those weird moments of satori, I realized something about Sharkscope: Unless the product has a hidden way of accounting for it --- and I don't believe it does --- the ROI numbers it generates for its customers carries an unknown skew. Sharkscope does not, to the best of my knowledge, account for tournaments where an overlay is in effect, therefore making ROI percentages a bit higher over the long run than they otherwise might be.

In the tournament above, I finished fifth, in itself my best cash of the year. But this tournament had a chunk of overlay, somewhere around 25%, and it occurred to me that a player who did nothing but hunt down events with sizable overlays would generate a much better-looking profile on Sharkscope than a similar player who played a lot of non-overlay events. Same player skills would yield different results. Sharkscope allows five searches a day, so I searched on the five highest finishers here besides myself.

You can see that all of them look to be really tough players, but is that the whole truth? It's possible that one or two of them just might be middlin' players who focus only on big-overlay specials --- I'm not saying that it's so, but that it could be. As for me, thinking back to my own tourneys played, I'd guess that my ROI is 2-3% inflated over what it should really be , due to unaccounted overlays. It's not a big deal, but it's a hidden factor nonetheless.

Lesson: If you use a Sharkscope or something like it, use it only in a general sense. Specifics can't be trusted.


John said...

I'm not quite sure what you mean by "overlay". Would you clear that up for me please.

I have found Sharkscope valuable only in the sense that it can give you an overall feel of the game you're in. I have seen players rated as shark tank almost immediately and others rated as goldfish, win multi-tables.

One does have the ability to opt out of their reporting, at least in the sense of how much one has won or lost, they will still show your "rating" and roi.


Nick said...

Well...John, just look up "overlay" on google. An overlay is money that is added to a tournament pizepool beyond the buyins and as such "added money".

You're quite correct in saying that this would give players of equal skill a different average ROI but poker is a game of high varriance and all this information is very subject to varriables anyway.

I personally use sharkscope to assist in staking other players and I want to know exactly how profitable they are. If that's through good game selection, that's fine.