Mean reversion or have I forgotten how to play?

[spots123]

Ok, perhaps just a cry for a pep talk here. But after playing my first 100 SNGs at pokerroom $10+1 I had done pretty well, ITM and ROI both almost 50%. Now, I haven't really changed the way I play but have dumped 21 games in a row. Best finish in any of them, 5th. Did I forget how to play or is it mean reversion? Thanks in advance.
Spots

[J-Lo]

21 in a row seems like alot,but most would agree this could be normal variance.

[Karak567]

I dumped 12 in a row today after a 40 % ROI over the last week.

Normal variance... I hope.

[ilya]

A lot of it may just be variance, although your sample size is small. However, 21 OOTM is a big streak. Are you sure you're not tilting?

[11t]

Look over hand histories and be honest.

[Karak567]

I had AA and KK busted in 5 of the tournies today... so I think that had a lot to do with it for me.

[AtticusFinch]

Let me be geeky for a moment and throw in an explanation of mean regression, because you clearly have the wrong idea.

Mean regression does not mean that you can expect to have a bad run after a good one, so it all "evens out". Assuming independent random trials (for simplicity, I know this is not wholly accurate, so save the flames [img]/images/graemlins/smile.gif[/img] ), a run of 10, 100, or 1000 wins in a row has no effect on the likelihood that you'll win next time.

Regression to the mean is really an expression of how your results smooth out over time after a large number of trials. Let's say your ROI is 25%, but you happen to win your first 20 tourneys in a row. Your mean result will be way off from your "true" ROI for a long time. But if you then play 10000 tourneys that average out to roughly your true ROI rate, those first 20 will have a negligible effect on your overall average, and your mean result will come closer and closer to your true ROI.

It's just the tendency of a large number of trials to overwhelm short term spikes. Nothing more.

[skipperbob]

U better hope that Irieguy is in a good mood when he reads this [img]/images/graemlins/grin.gif[/img]

[spentrent]

21 OOTM in a row is A LOT. Where's that thread that predicts how often a 45% ITM player will lose 12 in a row? I dunno, but it's not very often. Perhaps you went on a great card run, got over-aggressive. Did you say this is your first 100 games ever?

[spots123]

No, not first 100 games ever, just first 100 since I started keeping track of it with the spreadsheet posted on the site a couple of times. Could be I got a bit more aggressive, but my current bad streak is spread over a two week period which I would hope would mitigate possible tilting.