Props to PokerStars for Quad Shootout roll forward

[Wayne]

Recieved in an email:
=============

Hello,

As you are doubtless aware, PokerStars suffered some system problems Monday night. The Quadruple Shootout you were playing in was canceled along with all other tournaments running at the time. The "roll forward" method we use is described on this page:

http://www.pokerstars.com/Tournament_Cancellation.html

Unfortunately, the formula as described on that page doesn't apply very well in a Shootout format. Players who had fewer than 4146 chips were overpaid, and players who had more were underpaid. Those that were overpaid were permitted to keep the overpayment. Those that were underpaid have received a credit to their account for the difference.

A mathematical profile of the problem and its solution follows, but if that does not interest you, then please simply jump to the end of this message to find your user ID and the amount of your credit in the list appended to this message.

Again we would like to apologize for the difficulties Monday night. Such circumstances are quite rare at PokerStars, and we hope our handling of these refunds demonstrates our dedication to serving you, our valued customers, in the best manner possible.... even when the circumstances aren't quite the best.

Good luck in your next event, and thank you for choosing PokerStars.

Best Regards,

Jeff
PokerStars Support Supervisor

---

Mathematical analysis:

The reason the formula failed in a Shootout is because it computes 50% of the pool among ALL players... and all players are not equal. Each table is a universe unto itself. Here is an example:

>>At the time of cancellation there were 418 player remaining, and >>your chip count was 9,000. Total chips in play were 1,944,000.
>>
>>Prize pool divided equally: $12,960.00/2 = $6,480.00
>>Prize pool divided based on chip count: $12,960.00/2 = $6,480.00
>>
>>Your share in money equally divided: $6,480.00/418 = $15.50
>>Your share on chip count: $6,480.00 x (9,000/1,944,000) = $30.00

This player had won out his first table. On his $10 buy-in, he has accumulated the equivalent of 6 buy-ins, $60 plus his entry fee. But because it spreads 50% of the prize pool over ALL 418 players (instead of 216 table winners), he gets shorted on that half of the distribution.

A player's total refund in a shootout should be:

[$X * N^R] * [(C / (S * N))] + F

Where $X is the buy-in, N is the number of players per table, R is the round number, S is the starting stack, C is the player's chip count, and F is the house fee.

e.g. in this Quad shootout with a $10+$1 buy-in, on the first round, with 6 players per table, a player with 9000 chips should get:

[$10 * 6^1] * (9000 / 9000) + 1 = $61

A player with 3000 chips on the SECOND round should get:

[$10 * 6^2] * (3000 / 9000) + 1
$360 * .33333 + 1 = $121

================================================== ================

What we did to correct this:

We were unable to retrieve each player's EXACT stack from the database.... and retrieving each stack from the hand histories would have been tedious. However, there is a method to get very close to the chip stack, with the only error being one of roundoff.

The incorrect formula awarded $16.50 to each player (half the prize pool divided by 418 players, plus a dollar for the house fee), and also awarded half the prize pool proportionally by stack. This reduces to this formula:

$6480 * (Stack / 1,944,000) = $Award - $16.50

Solving this equation for "Stack" gives us:

Stack = [ ($Award - $16.50) / $6480 ] * 1,944,000

Because we knew your award as determined by the errant roll-forward forumla, we plugged that award into this formula to get your chip stack at the time of the crash (within a few chips give or take).

We then used that chip stack in the correct formula to calculate the difference owed to anyone that was shorted. The results of these calculations are in the table below.

================================================== ================

[smoore]

I 'stars.

[smartalecc5]

Man, if only partypoker people were this smart and intelligent. Nice job pokerstars.

[astarck]

If I got something like this from party I think I'd just delete it and pass it off as spam.

[OrcaDK]

[ QUOTE ]
If I got something like this from party I think I'd just delete it and pass it off as spam.

[/ QUOTE ]

Those are my words! Such a mail would go straight to my scam/junk mail folder too.

[Amid Cent]

Ten bucks says Lee Jones helped them figure out that formula.

[Lee Jones]

[ QUOTE ]
Ten bucks says Lee Jones helped them figure out that formula.

[/ QUOTE ]

You lose.

HostJeff worked that up on his own. Presented it to me as a fait accompli and I said "Damn - that's clever."

He had already used it to rebate everybody.

I have said this before and I'll say it again: the people that I work with are stupendously bright, hard working, and (as you can see) very very clever.

I get to take an inordinate amount of the credit - it's one of the perks of the job.

Best regards,
Lee Jones

PokerStars Poker Room Manager

[speedrissr]

Another example of why PS is heads and above the best place to play MTT's. Technical issues almost never happen and when they do, PS does it's best to get a fair resolution. I've even gotten bumped from 4th to 3rd in a SNG after it ended (allowing me to cash) when they discovered some online collusion.

Al?

RLR

[BlueBear]

OMG! Well good job by Stars, if it was another site, they would just say "bad luck".

[steelcmg]

Stars was the site i stared at and its by far my favorite. If it wasnt for BW to get my account up i would never have left stars. But as soon as i get more money right back i go.