The one question candidates want answered is "Why don't recruiters call me back with updates? I feel my calls are being screened." This tells me that realistic expectations were not established. A great solution is to share written expectations with candidates to eliminate confusion.

Most of your time is spent matching your candidate's skills and priorities to open jobs. Third-party recruiters are also marketing candidates to their best clients. Explain this to your candidates, so they realize you are working on their behalf throughout your day.

If you provided updates to every candidate you represent,
you'd have no time to match them to job opportunities.

If your candidates have changed anything on their resume, or interviewed with another company, ask them to call you between the hours of 4-5:00 PM, so you can fine tune your efforts on their behalf.

Candidates should expect feedback after interviewing with one of your Hiring Managers. If they are screened out, ask your hiring manager what you missed, so you can share the information with each candidate.

Once candidates realize the benefit to THEM, for you not providing constant updates, this problem is resolved!