The Investigator’s Purpose: Addressing the PI Shortage

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If you’ve led a clinical development program, you likely know something all too well: there’s a constrained pipeline of qualified principal investigators (PIs), and a high prevalence of “one-and-done” PIs.

About half of all PIs conduct only a single clinical trial in their careers before walking away. This isn’t simply another negative byproduct of turnover. It’s a drain on the industry’s capacity to deliver new therapies to patients who need them.

As we celebrate Clinical Trials Day 2025 under the theme “Powered by Purpose,” I want to focus on supporting PIs, which can help fulfill our collective purpose of advancing medical science and improving patient lives. After all, even the most groundbreaking molecule won’t reach patients without PIs there to shepherd it through clinical development.

The Steady Exodus: Why Investigators Leave

Before we can solve the PI shortage, we need to understand why talented physicians are abandoning clinical research after just one trial (or, just as bad, not even considering research as a career pathway). A comprehensive study conducted by Duke University and the U.S. Food and Drug Administration uncovered several key factors:

  • Workload imbalance (63.8%): Physicians struggle to juggle research responsibilities alongside their clinical practice.
  • Time required for trial implementation (63.4%): The sheer hours needed to initiate and maintain a trial overwhelm many first-time investigators.
  • Regulatory and safety reporting burdens (56.5%): Complex documentation and vague requirements create frustration and administrative fatigue.
  • Financial dissatisfaction (46%): Compensation structures often fail to adequately account for the true effort involved.

Additionally, many investigators (44.4%) reported interest in conducting another trial but found no opportunities available to them. A missed connection that costs our industry potentially valuable talent. These challenges have intensified as trials have grown more complex. Over the past decade, trial complexity, as measured by endpoints, inclusion/exclusion criteria (number or precision), protocol amendments, and more, has become more complex across all phases and across therapeutic areas.

This complexity, combined with global coordination requirements and shifting regulatory frameworks, creates a daunting environment for new PIs. Having abruptly entered the centrifuge of clinical trial oversight, many want out.

The Cost of Continuous Turnover

Any reliance on constantly recruiting new, inexperienced PIs and sites creates significant inefficiencies. According to a Tufts Center for the Study of Drug Development survey, contract research organizations (CROs) take 5.6 weeks to start a clinical study at sites they’ve worked with before, versus 11 weeks when new sites are involved. That’s nearly double the time.

Each time a physician conducts only one trial and exits research, we lose the investment made in their training and forfeit the efficiency gains that come with experience. This perpetual cycle of recruitment, basic training, and subsequent departure significantly hampers our ability to accelerate clinical development.

Put bluntly, for any sponsor or CRO, an “inexperienced” PI or site may as well be classified as “unpredictable.”

Unpredictable enrollment, performance, and quality. When tried, trusted sites and PIs are available, why would a sponsor select research-naïve sites and PIs?

But relying solely on established PIs creates bottlenecks too. Sites can become overburdened, geographic diversity can be constrained, and trials may miss opportunities in untapped patient populations. I’ve been fortunate to work with numerous partners showing tremendous interest—and investment—in PI engagement. Sanofi, Pfizer, Moderna and other forward-thinking companies come to mind. They provide training that will benefit the PI beyond any specific protocol.

Engaged, well-supported PIs bring value to the entire clinical trial ecosystem. Beyond environmental sustainability, clinical trials need to be experientially sustainable for PIs. Even the most experienced and enthusiastic among us can find ourselves knee-deep in paperwork.

Mentorship: The Missing Link in Investigator Development

Sponsors need qualified investigators, and talented physicians want to enter research. Structured oversight can make welcoming new PIs to clinical research feasible and advantageous for all involved.

Against this backdrop, mentorship has emerged as a powerful solution. In my role, I’ve seen firsthand how structured guidance from experienced investigators can transform a potentially overwhelmed first-time PI into a confident, efficient clinical researcher. Here are thoughts from two new incredibly talented PIs:

Dr. Daniel Williams in Anderson, S.C.: “Mentorship has been crucial to my development in this role. I value the time I’ve spent with other PIs who have extensive experience in research, and I’ve gathered a wealth of knowledge from them as I’ve transitioned from clinical medicine.”

Dr. Dennis Tsang in Huntington Park, Calif.: “At the site level, Dr. Hsia has been a great mentor to me, with decades of research experience under his belt. At the organizational level, Dr. Overcash provides regular supervision and feedback with frequent check-ins.”

Physicians don’t typically leave clinical research because they lack interest or see no value in it. Rather, they depart because the path forward seems too burdensome to navigate alone.

As with other patient-facing roles in clinical research (sub-investigators, site directors, clinical research coordinators [CRCs], etc.), productive PIs can be great cultivators of other productive PIs. If there’s one call to action I could put forward to experienced researchers, it would be this: take seriously the value you could provide as a mentor.

A Systematic Approach to Building the PI Pipeline

Recognizing this opportunity, my team developed the Principal Investigator Onboarding and Training (PIVOT) Program. This comprehensive system addresses the primary reasons investigators leave while providing the support and guidance needed to develop long-term research careers.

Sites of any scale can adopt facets of this program. Sponsors looking to reinforce their relationships with new PIs may also do well to understand the most impactful areas where they could provide training content or facilitators.

PIVOT combines four essential elements:

  • Immersive Bootcamps: Hands-on training in practical skills, regulatory compliance, enrollment strategies, investigational product management, and lab processes.
  • One-on-One Mentorship: Weekly sessions with seasoned investigators, providing personalized coaching and guidance through complex trial scenarios.
  • Digital Learning: Self-paced modules covering Good Clinical Practice, ethics, and operational systems, leveraging partnerships with trusted organizations like the Association of Clinical Research Professionals (ACRP) and Advarra.
  • Leadership Reviews: Regular strategic progress reviews to ensure alignment with organizational goals and continuous professional development.

Crucially, PIVOT doesn’t just provide training, it creates an ecosystem of support. Each new PI receives:

  • An experienced CRC to assist with day-to-day trial activities.
  • A dedicated regulatory specialist to navigate compliance requirements.
  • Site managers who coordinate staffing, logistics, and patient scheduling.
  • A structured progression of responsibilities that builds competence and confidence.

So much of this just comes down to people and culture. This system creates multiple layers of expertise and oversight that directly address the primary pain points new investigators face: workload balance, time management, regulatory burden, and professional satisfaction—all things that would influence any company’s culture, but do so disproportionately given a PI’s role at a research site.

How Sites Can Support PI Retention

Beyond mentorship, multisite research organizations (and site networks) have a structural advantage to help retain investigators. As a scaled business, multisite organizations can distribute administrative burdens that might otherwise fall to individual PIs at independent sites.

Everything from centralized business development, regulatory, finance, and patient engagement teams can handle many tasks that would typically consume a PI’s time at a non-networked site. This economy of scale allows investigators to focus on higher-impact activities where medical expertise adds the most value. You want PIs immersed in research, not negotiating contracts, troubleshooting a freezer issue, or hunting for lab kits.

As we’ve done at Velocity, multisite organizations can also pool resources to develop standardized training and mentorship programs. Moreover, standardization among systems and processes can simplify knowledge transfer among studies, reducing the learning curve for each new protocol.

A Community of Purpose

In this industry, we have a clear line of sight to the importance of what we do: our work improves lives. But even aside from the altruistic angle, research offers motivated investigators a way to provide more care options to patients in their local communities and build rapport with leading and emerging pharma companies globally—a vast professional community that many physicians will not get to experience.

Perhaps most importantly, early integration into local and global research communities can instill PIs with a sense of shared purpose. Clinical research can be isolating in traditional practice settings, but a network of peers facing similar challenges creates camaraderie and collective problem-solving. Aside from providing an abundance of educational resources, this is why ACRP is an essential part of the research community.

As we commemorate Clinical Trials Day 2025, I challenge our industry to view the PI shortage as an opportunity to reimagine how we develop and support clinical investigators:

  • Prioritize mentorship: Create formal programs that pair experienced investigators with newcomers to the field.
  • Streamline administrative burdens: Use technology and support staff to help physicians navigate processes that don’t require their medical expertise.
  • Build communities of practice: Foster connections between investigators, both within and outside of your organization, to share knowledge and provide peer support.
  • Invest in training: Recognize that comprehensive initial training yields returns through improved efficiency and quality.
  • Create clear career pathways: Show physicians how clinical research can enhance their professional development and impact.

We can build a sustainable pipeline of qualified, engaged PIs who remain in research for the long term.

On this Clinical Trials Day, let’s commit to strengthening our workforce, not just for the benefit of our industry, but for the millions of patients worldwide who depend on clinical research to develop the therapies of tomorrow. Let’s help PIs fulfill their purpose to bring those therapies to life.

Authored by Brandon Essink, MD, CPI, Chief Physician Officer at Velocity Clinical Research, the world’s largest dedicated clinical trial site organization with more than 80 sites across the U.S., U.K., and Europe. Velocity is proud to be the official sites sponsor for ACRP’s Clinical Trials Day 2025.