I could have used this knowledge not just on my first job but when I was interviewing for my current job 14 years ago. The interviewer asked me what salary I was seeking which was, in hindsight, an obvious trap. If I gave too low a figure, they'd "grant" me that instead of the higher figure they were thinking of. I had a figure in mind but got nervous that I wouldn't get the job if I went too high. I wound up taking about five thousand off my "figure in my mind" - and was promptly awarded that. I'll never know if I would have gotten more money had I gone higher, but that moment of insecurity still bothers me to this day.
This is where soft skills comes in.
The goal is to not be specific, but to make it such that you lob it back to them. Remember, let them make the first move - you should never ever announce a number.
So if they ask, try to deflect it back to them - "I don't have a specific number in mind, however, I do know what similar positions pay elsewhere and I expect Initech to pay comparable rates".
If they ask for a specific number, then again, deflect it - "Well, according to this survey, someone in my position with the responsibilities given would be making anywhere from $XXX to $YYY" If you know the median salary, then state that "... with a median of $ZZZ".
Yes, you DID research what similar positions pay in your area, right? I mean, that's how you decided you were underpaid?
Let them pick the specific number - you choose whether or not to accept based on that number. By giving them a range, you let them figure out and guess what you'll take. You stated a range which you researched and let them figure it out. If they decide the low end is all you deserve, it's better to find that out rather than wonder.
And $5000 is not a lot of money at the end of the day - after taxes, you're really only looking at $3600 or so, which is $300 a month.
The key to negotiations, especially salary, is to let the other guy pick the first number. If it's too low, you're free to reject the offer, and you can respond "to be honest, I didn't feel the compensation or benefits were adequate for my needs to change positions". Again, no numbers. If they ask, go ahead and mention the range. If another salary survey comes out, mention that too.
A job has to be considered for the whole - realizing that there are big changes, and there are little ones. $5000 is not a lot of pay in the end to worry about if you're already making $95k or so. If they are grossly up or down, then something might be up - $12K might be the smallest unit where salary matters because that's $1K/month or after taxes the better part of a grand still.