For the past 18 years, Tom Gimbel, a recruiter in Chicago, has helped thousands of people find jobs in accounting, finance and human resources. Lately, the process has been slowing down as candidates go through more interviews, more screenings, more tests.

“What’s really dragged it down quite a bit is technology,” said Mr. Gimbel, the founder and chief executive of the LaSalle Network. “So many companies are using technology portals and databases with their people.” They may be getting better hires out of the process, but...