Estimating opening ranges with small samples

[fjuanl]

Reshoving is pretty important in MTTs and to do that well you have to be able to guess someone's opening range. For awhile I would just look at someones PFR and assume its close to correct. If they're in a steal spot look at the ATT (attempt to steal) but most of the time you have <10 samples so its tough to make good guesses. Every once in awhile I glance at the 'Raise first' stat and come across some interesting numbers like I did in this hand:

PokerStars No-Limit Hold'em, 55 Tournament, 1250/2500 Blinds 250 Ante (8 handed) - Poker-Stars Converter Tool from FlopTurnRiver.com

MP2 (t30851)
CO (t117316)
Hero (Button) (t44729)
SB (t106813)
BB (t22098)
UTG (t142388)
UTG+1 (t70833)
MP1 (t55178)

Hero's M: 7.78

Preflop: Hero is Button with K, 10
UTG bets t5000, 5 folds, Hero ...

UTG in this hand was 15/13 (VPIP/PFR) through 60 hands. If you just look at PFR and figure its around ~10% because he is raising from UTG, shoving here would a horrible horrible mistake. But look at his HUD stats closer:



Notice that his 'Raise 1st' stat totals at 28%. (The numbers in parenthesis are the sample sizes.) This stat keeps track of how often someone makes a raise when its folded to them. So this villain had 25 chances to 'raise 1st' and made a raise 7 times (7/25=28%). Then you'll notice that the majority of his chances to make an open raise came in early position (EP)

Obviously we're dealing with tiny sample sizes here, but when you see stats that high you start to question things.

1) What do you think his 'true' opening range is?

2) Do you think it would be smart to use the 'Raise 1st' stat in your HUD?

[baudib]

I think it's interesting to know but it's hard to know what to make of a few hands. It'd be helpful if you observed any hands that went to showdown, so if he shows up with QJo UTG, you know he is opening wide there. I'd like to have a different hand here, but I suppose KT = AT vs. his continuing range.

[drmcboy]

I voted 10-15%, I can't get past the unlogic of using this sample to judge EP while ignoring it for LP.

I do like the idea of using raise 1st instead of pfr, might have to look into that. I would do both but 4 stats (VPIP/PFR/3 Bet/Att steal)seems to be about the limit of what I can have without it driving me crazy.

[KoRnholio]

I do like the idea of using raise 1st instead of pfr, might have to look into that. I would do both but 4 stats (VPIP/PFR/3 Bet/Att steal)seems to be about the limit of what I can have without it driving me crazy.

The idea of raise 1st is interesting, but when I look at that epicly huge chart on my HEM HUD while playing, I can't make heads or tails of it. I have VPIP/PFR/3b/ATS and that's all I really use.

I see what the OP is getting at with the fact that it looks a lot like this guy is opening from EP way more often than he should be or that his 15/13 stats indicate. Have you seen any of the hands he's raised from EP at a showdown?

Since I play fewer tables than most, these are the kinds of things I will take note of. If I saw a guy raising often from EP, I'd make sure to take a second to watch and see what he shows down once or twice. All it takes is one unusual hand (say 87s or A9o with these stack sizes) and it'll go into my notes for future reference.

If I had to guess at his UTG opening range, using the Raise 1st stat as my read. I'd guess 20% or so. Still, to make this move with KT, knowledge of how often/light he'd call a raise or shove is also needed. The stack sizes are a bit akward for this move I think. If you just 3bet it to 16k or so, he may well call and take a flop given his stack size.

If you shove, it looks bluffy/weakish (since you wouldn't overbet shove QQ+ there) and he might well look you up with AT+,KJs+, 66+ (9.5% of hands, about half his range). So if he folds half his 20% range, you net +10.8k. If he calls half the time, you're a 2:1 dog when called, netting about -11k on average.

In summary, it looks like if he's opening more than 20% UTG and/or calling with less than the top 10% of hands, it's marginally +EV to shove here.

[baudib]

I'd be surprised if he's calling 9.5 to a shove. need to factor in the blinds waking up with a hand, too.

[revolvingiris]

I would fold and wait for a different spot. 60 hands can mean villain just happened to run well from EP. I fold and wait till I know more about them to start making plays.

[fjuanl]

Over a 160k hand sample, my overall Raise 1st is almost double my PFR. It obviously varies quite a bit by position, but it can sort of give you an idea for how different these two stats can be.

In summary, it looks like if he's opening more than 20% UTG and/or calling with less than the top 10% of hands, it's marginally +EV to shove here.

If you take into account SB and BB getting a hand, it becomes slightly -EV. Here's the breakdown of EV [according to sngwiz], assuming he calls the shove with top 8% (roughly 66+ AJo+ ATs+) and the blinds call with top 3% (JJ+ AK)

15% open: -1BB
20% open: +0.2BB
25% open: +0.8BB
30% open: +1.28BB

These are very big changes in EV. Basically every time you widen his range by 5%, you double the amount of hands you can reshove with.