What is the hardest part of the hiring process? A survey of more than 2,800 senior managers conducted by professional staffing firm Robert Half International Inc. (NYSE: RHI) found that 35% said “generating interest from qualified candidates” was the most difficult.

It was followed by “asking the right interview questions” at 20% and “developing compensation packages and negotiating salaries” at 19%.

Robert Half also asked about the most common reason candidates give for turning down a job offer. Cited by 30% of senior execs each, the two most-common reasons were compensation and benefits being lower than expected and that the candidate accepted another job offer or counteroffer. The next most-cited reason, at 13%, was limited opportunities for career growth or advancement.

Another question posed was “aside from poor performance, what’s most likely to lead to a failed hire?” The top answer, cited by 30%, was a mismatched skill set. Next was unclear performance expectations at 26% followed by personality conflicts at 23% and failure to fit into corporate culture at 21%.