Short answerPhysicians refer a median of five patients into clinical trials per year, less than 0.2% of their patient volume, even though 90% say they are comfortable discussing trials, according to Tufts CSDD. Nearly 30% of physicians and 45% of nurses never heard back from the site after referring. Only 9% of physicians say fear of losing patients affects referral.
Referral rates and barriers
| Statistic | Figure | Source |
|---|---|---|
| Physicians and nurses surveyed | 755 and 1,255 | Getz, Applied Clinical Trials |
| Median patients referred per year, physicians | 5 | Getz |
| Median patients referred per year, nurses | 2 | Getz |
| Share of physicians' patient volume referred | Less than 0.2% | Getz |
| Physicians comfortable discussing trials | 90% | Tufts CSDD |
| Physicians citing fear of losing patients | 9% | Tufts CSDD |
| Physicians never contacted after referring | Nearly 30% | Tufts CSDD |
| Nurses never contacted after referring | 45% | Tufts CSDD |
| Referral likelihood, clinical practice vs hospital based | 2.7 times higher | Tufts CSDD |
| Odds of likely referral when close to a research center (Alzheimer's survey) | About 4 times higher | PubMed |
Reaching physicians
| Statistic | Figure | Source |
|---|---|---|
| Physician response to mailed invitations (13,251 oncologists) | 11.8% | BMC Medical Research Methodology |
| Physician response to email invitations | 4.5% | BMC |
| Emailed physicians who opened the email | About a quarter | BMC |
| Licensed nurse practitioners in the US (2025) | 461,246 | AANP |
Where patients are managed
| Statistic | Figure | Source |
|---|---|---|
| Antidepressants prescribed by primary care | 79% | Yale Journal of Biology and Medicine |
| At risk primary care patients with COPD who knew their diagnosis | 32.7% | CMAJ |
What is the takeaway?
Physicians are willing but uninformed and rarely followed up with. The gap is operational: who reaches them, with what information, and how consistently. That is exactly what can be systematized. See how to build a physician referral network.
Get your study in front of the right local physicians
TrialNotice builds a physician referral pipeline around one active study. We identify relevant local physicians within driving distance of your site, send study aligned direct mail, follow up by email and LinkedIn, track engagement with recipient level QR codes, and route warm responses into your site team's workflow.
Talk to TrialNoticeSources
- Applied Clinical Trials, "Tufts CSDD Study Explores Low Recruitment Rates"
- Ken Getz, Applied Clinical Trials, "Rebooting the Statistic That 5% of Eligible Patients Participate in Clinical Trials"
- "Predictors of physician referral for patient recruitment to Alzheimer disease clinical trials," Alzheimer Disease and Associated Disorders, PubMed
- Murphy C.C. et al., "A randomized trial of mail and email recruitment strategies for a physician survey on clinical trial accrual," BMC Medical Research Methodology
- Barkil Oteo A., "Collaborative Care for Depression in Primary Care," Yale Journal of Biology and Medicine
- "Prevalence and underdiagnosis of COPD among patients at risk in primary care," CMAJ, via Global Family Doctor
- American Association of Nurse Practitioners, NP Count Methods Snapshot (October 2025)
