Of all the questions I get from HR professionals, this is by far the most common. Managers often fail to put much time into recruiting for a variety of reasons. Too many rules, guidelines, legalities and procedures, all of which either intimidate or frustrate most managers. They don't see the immediate business impact or the ROI of great hiring. HR doesn't do its job.
Many recruiters operate on the principal that more is better.
In other words, the more resumes you give to a manager the better. In fact, nothing can be further from the truth. If you physically watch a manager go through a stack of resumes you'll find some amazing things. The volume alone is intimidating. Eventually they will pick up the stack and take them home with the best intentions of reading them.