I’m struggling to understand what sort of circumstances call for us to pick our strongest draws as raises and when we pick instead our weakest draws, and keep our strongest draws in our calling range.

I understand that there are situations when it is better to keep our best draws as part of our calling range, because we don't want to raise and then have to fold a draw that has a great deal of equity, but I haven't quite figured out how to recognise these different spots.

In an attempt to solve this myself I have looked at 20 odd hands, either played by or recommended by professionals and tried to find a pattern. I have tried to focus on position, opponents perceived aggression, the strength of villain's range in comparison to ours, and finally how well our hand connects with the board (that is how many value combos we have)...

Out of 20 hands so far I have found just 4 in which hero chooses to call (instead of raise) a high equity drawing hand, and by this I mean an 8-outer (I think all the examples I have found have been OESDs). The pattern which seems to be emerging is this: We are the PFC, we are facing both pre and post-flop aggression, and we have few value combos (9 or less).

Maybe this is a long winded way of going about this, maybe I'm focusing on the some of the wrong details, maybe I'm missing something simple? Anyway, any help with this will be greatly appreciated!

It’s a matter of fold equity and likelihood to be paid off for stacks when you do hit. Which is a matter of player tendency and board vs range composition

does anybody agree? Could someone expand on this if so..

If the example hands being studied are mostly oesd, that may or may not be high enough in range to be considered a “high equity draw”.
A lot of oesd hands are good bluff candidates because it is basically “jack high”.
Also, many oesd draws feature card removal to the range of a potential caller to our raise.
The strongest draw that I can think of that is generally found in a flat call range would be the nut flush draw, with an ace. So, ace high and a nfd plus maybe a bdsd to go with it, might be the best hand anyway and as such is a lesser bluff candidate.
It all depends on the hands you are studying, of course.

1. Stack depth. If a 3 bet is likely which will be the case at shorter stack depths, then raising low equity draws is better. If we expect to not be 3 bet too often, raising high equity draws is better.

2. In multi way pots, raising nutted draws is often a mistake. We want someone else to come in with a dominated draw. But raising non nutted combo draws is very appealing because we want to push out higher draws.

3. Raising draws oop is more appealing. It's hard to get paid off by just flat calling oop.

Having a nut advantage or nut blockers would also reduce the likelihood of being 3bet off your equity, making raising more appealing.

Raise with your stronger draws when your opponent is more likely to respond with a fold or call (e.g., you have range advantage, villain is more passive, board is more textured, villain's range is smoother), and raise with your weaker draws when your opponent is more likely to respond with a fold or raise (basically the opposite of everything above).

I’m working on an Excel VBA program that can analyze this situation mathematically.

Assume heads up and the turn card gives hero a nut flush draw (9 outs), which has equity of approximately 20% if he goes to showdown . Suppose hero checks and villain makes a pot size bet. If hero calls, his EV is 0.20*2 - 0.80*1 = -0.4, so folding is clearly preferable to calling.

Now let’s consider the hero raise option, in this case a check-raise. The new factor is fold equity. The model incorporates a fold equity function (actually several) which is dependent on bet size and has a general “lazy S” shape. The fold equity is low for small bets, it rises rapidly for mid size bets, and is high for large bets. Using Excel’s goal seek function for the fold equity function I chose, it told me that a raise of 3.6 gives EV =0, and any larger raise has higher EV. At a raise of 3.6, the fold equity was 56%.

I suppose the point of this posting is that OP’s question can be addressed mathematically and the result can then be adjusted for factors that the math model does not explicitly consider.

Can you explain ur equations a bit more

Aesah's general rule (post #7) seems solid.

Bear in mind that a GTO solution would involve mixed frequencies for almost every combo in your range. It's actually quite rare that you should always call all your OESDs, or always raise them. The GTO solution would typically include calling with some FDs, OESDs and gutters, and raising with some too, and each of those combos could be called or raised at different frequencies. To avoid exploitation, you almost never want to play all your flush draws, or all your straight draws exactly the same. You often want to be able to show up with the nuts on the river whether you called or raised on the turn.

e.g. If you have 98 on AJ72, you might call or raise the turn, so that if the ten comes on the river, you can have the straight whether you called or raised the turn. If you always raised the turn with 98, then an opponent knows you never have 98 if you flat it. The same goes for flushes. You need to call some FDs on the turn, so that you can rep them (with 98o that missed, for example) if the flush completes on the river.

P.S. All that said, if you want to pick some SDs to raise more often (as a bluff, expecting to elicit a fold) than flat, you're often better off raising the ones that have the least amount of showdown value. i.e. 98s is unlikely to win at showdown on AJ7 (it's 9-high, and making 3rd pair isn't great), but KQ might, so in many cases it would make sense to flat KQ, but raise 98s.

Not all “strong” draws are equal.

What would you rather have, a gutshot with 4 clean outs to the nuts or a flush draw to the 4th nut flush?

As arty said, the correct play is to mix it up.

But in general if my draw has nutted potential I will be more aggro with it. If my draw has less outs I will be more aggro with it (or fold). If I have a ton of outs AND nutted potential I’ll mix it up.