A number you can source is worth far more in a negotiation than a number you feel.
Sources in order of usefulness
1. Job ads that publish bands for the same role and region
2. Published industry salary surveys
3. People doing the job, asked directly and privately
4. Aggregate self-report sites, treated with caution
Look at spread, not midpoint
Knowing a role pays 55-80 tells you far more than knowing it averages 66. Negotiation happens in the spread.
Cite the source
"Three current listings for this role in this region publish 60-75" is checkable. "I read online that this pays more" is not.
Common questions
Are salary comparison websites accurate?
Directionally, at best. They rely on self-reporting and skew high. Use published job ad bands where you can.
Should I quote my research in a negotiation?
Yes, briefly and specifically. A checkable source strengthens the position.