Pay transparency in trades job listings — does it actually matter?

Since launching VoltGrid Jobs, we've noticed listings without salary ranges get way fewer clicks than those that include them.

Wondering if others have seen the same. Or if you've worked in the trades, was pay transparency what actually moved you to apply, or did something else matter more? Location, per diem, union status, project type?

Trying to figure out what to push employers on when they post.