Hypothetical situation time. I'm a job seeker and my minimum acceptable salary is $100k. You're a recruiter and your range is $80-$120k. Neither of us know the others' number.
If I make you say a number first, you would start at the bottom of your range. (Why not?) Now I'm "negotiating up" to my minimum.
Alternatively, I go first and anchor at $150k. Now it's much more difficult to lowball me at $80k, and we'll probably "negotiate down" to your maximum.
The key with this technique is setting a good anchor. Too high (e.g., $200k) and you'll just walk away. Too low (e.g., $120k) and you'll whittle me down because you know you can negotiate.
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Bottom line is knowing what you're worth and quickly testing whether you're in the ballpark. If you go into interviews without having a sense of whether the company will give you a competitive offer, you're wasting everyone's time. (And you have a bad HR department.)
Don't use ranges: the employer will hear the lower number. Just say, "The market rate for this kind of role is $150k base. I'd look for a competitive overall comp package, and we can talk about salary, bonus, and equity. Is that what you had in mind?"
You'll get one of three answers:
1. "Yes, that's in range." (And you can probably negotiate up.)
2. "No, that's too high. We were thinking $x." (Now you know where you stand, and how far apart you are. <20% is negotiation. Note that if they don't give you $x, don't give another number: you're just negotiating against yourself.)
3. "Ehh, it's on the higher end, but I think we can make this work." (Might actually be #1, but otherwise means you're in the sweet spot.)