Properly Quantifying Backdoor Outs

[SixForty]

Something that HoneyBadger mentioned in a post recently got me thinking more about this topic. How much do we value a backdoor flush draw or backdoor straight draw?

If we do the math, a back door flush draw is the equivalent of 0.978 outs. That is, a backdoor flush will come in by the river with the same frequency as a hand that has 0.978 outs. This can be effectively rounded up to 1 out just to make life easier.

However, most common literature (at least, the things that I have read, which I admit, may not be much!) says that you can actually value a backdoor flush at 1.5 outs. The reasoning given is that you aren't commited to see the river if you don't catch a four flush on the turn. So you won't always be chasing it to the river.

This makes perfect sense, and I've always given my backdoor flush draws the equivalent of 1.5 outs. Unless it's a very low flush, against lots of opponents, and there's a chance I can lose to a higher flush. But still, for the most part, I use that 1.5 outs number.

But what HoneyBadger said in this thread here got me thinking.

If I have a hand that I'm planning on seeing the river with anyway, then I can't really add that extra half an out? I should only be valuing my backdoor flush as 1 out, correct? Because I can't claim that I'll fold the turn when I don't pick up a four flush?

For example, let's say I have an open-ended straight draw with a backdoor flush draw in a four-way pot that was raised preflop. The pot is big enough that I'm going to see the river with my straight draw alone, so I can't really count my backdoor flush draw as more that one out.

But if I have a gutshot straight draw with a backdoor flush draw, I can consider the flush draw as 1.5 outs, since I'm often peeling on the flop but folding on the turn unimproved.

So if I have a hand that commits me to see the river otherwise, a backdoor flush draw only adds 1 out? But if I have a hand that I may call to see the turn, but can still fold there unimproved, a backdoor flush draw can add 1.5 outs?

Does that make sense?