Few topics in Medical Affairs generate as much recurring discussion as the terminology used to describe highly influential physicians and health care professionals (HCPs). While some organizations have attempted to move away from the term “Key Opinion Leader” (KOL) in favor of alternatives such as “Thought Leader” or “External Expert,” the term KOL remains deeply embedded within the pharmaceutical, biotech, diagnostics, and medical device industries.
The terminology organizations choose is not simply a semantic issue. These terms impact communication, influence organizational culture, affect training and engagement strategies, and reflect how Medical Affairs professionals approach scientific relationships with external experts. Over the past decade, some industry professionals have questioned whether KOL is outdated or overly commercialized. Others argue that it remains the clearest and most universally understood term.
Key Opinion Leader is historically the original and most widely used term within Medical Affairs. However, given the growing emphasis on scientific exchange and HCP engagement, the Medical Science Liaison Society sought to examine whether preferences for this terminology had changed over time.
In 2017, the Medical Science Liaison Society conducted the first-ever survey examining the preferred terminology used to describe physicians and HCPs whose opinions are highly regarded and influence other physicians 1. The global survey included 473 Medical Affairs professionals.
Table 1. 2017 Global Survey on Preferred Terminology: What term do you think should be used when referring to the physicians and other HCPs whose opinions are highly regarded and influence other physicians?
| Preferred Term | Percentage | Number of Participants |
|---|---|---|
| Key Opinion Leader (KOL) | 42% | 198 |
| Thought Leader (TL) | 14% | 66 |
| Medical Expert (ME) | 13% | 62 |
| External Expert (EE) | 6% | 27 |
| Other Terms | 25% | 120 |
| Total | 100% | 473 |
The findings demonstrated that although several alternative terms were being used across the industry, ‘KOL’ was the dominant and most recognizable term globally in 2017. Interestingly, the relatively large “Other Terms” category also suggested substantial fragmentation regarding terminology preferences at that time.
Over the last 10 years, some organizations began distancing themselves from the term KOL for a variety of reasons. Some believed the term sounded too commercially focused, while others felt the phrase “opinion leader” could imply influence beyond scientific expertise. In response, alternative terms such as Thought Leader, Medical Expert, External Expert, Key Thought Leader, Scientific Expert, and Opinion Leader began appearing within Medical Affairs.
Despite these efforts, many professionals continued using the term KOL in daily conversations and operational discussions. Having facilitated Medical Science Liaison (MSL) training programs at 87 pharmaceutical, biotech, diagnostic, and medical device companies in 22 countries, I have consistently observed that even for those organizations that formally prefer alternative terminology, discussions during training sessions almost inevitably revert back to the term KOL because of its familiarity, simplicity, and universal recognition.
To determine whether terminology preferences had shifted over time, the Medical Science Liaison Society recently conducted another global survey in May of 2026. Importantly, participants were specifically instructed to answer based on their personal preference, not necessarily the terminology used internally by their company. The global survey included 328 Medical Affairs professionals and revealed some interesting findings.
Table 2. 2026 Global Survey on Preferred Terminology: What is the best term to use when referring to physicians and other HCPs whose opinions are highly regarded and influence other physicians?
| Preferred Term | Percentage | Number of Participants |
|---|---|---|
| Key Opinion Leader (KOL) | 64% | 210 |
| Thought Leader (TL) | 25% | 82 |
| External Expert (EE) | 8% | 26 |
| Other | 2% | 10 |
| Total | 100% | 328 |
Interestingly, the term KOL has not only remained strongly favored but is now preferred by a significantly greater percentage of Medical Affairs professionals than in 2017. In fact, preference for the term rose from 42% in 2017 to 64% in 2026, representing an increase of more than 50%!
The findings suggest that despite ongoing debates regarding terminology, KOL continues to resonate strongly with Medical Affairs professionals globally. While alternative terminology, particularly Thought Leader, has gained traction, none have displaced KOL as the overall preferred term.
There are three broad possible reasons KOL persists so strongly across Medical Affairs.
First, KOL has become historically entrenched within Medical Affairs operations and strategy. The term has been used for decades in scientific congress planning, advisory boards, publication strategy, CRM systems, strategic engagement planning, and MSL training programs.
Second, KOL remains universally recognized. MSLs, Medical Directors, physicians, consultants, agencies, and vendors all immediately understand what the term means and commonly use the term. In global organizations where cross-functional and cross-regional communication is essential, universally recognized terminology provides substantial practical value. This continued focus on influential physicians and HCPs also aligns with broader discussions surrounding the measurable impact of MSLs and how scientific engagement with KOLs contributes to education, evidence dissemination, insight generation, and ultimately more informed clinical decision-making 2.
Third, the term is operationally efficient. KOL is concise, familiar, and easy to use in both conversation and written communication. This consistency is also important from a Medical Affairs operations perspective, particularly as organizations continue evaluating KPIs and metrics related to KOL engagement, scientific exchange, and field medical effectiveness 3.
There is also an important distinction between “Thought Leader”, “External Expert,” and “KOL.” Both Thought leadership and External Expertise may imply broader visibility, public influence, speaking presence, or social media engagement, whereas KOL traditionally refers more specifically to scientific and clinical influence among professional peers. As a result, many Medical Affairs professionals may view these terms as related, but not necessarily interchangeable.
At the same time, these findings do not suggest that alternative terminology lacks value. In some organizations, terms such as External Expert may better align with company culture, compliance philosophy, or strategic positioning. Ultimately, however, terminology alone does not define the quality or integrity of scientific engagement. Whether organizations use the term KOL, Thought Leader, or External Expert, the more important issue is how these relationships are approached, managed, and supported within an ethical, evidence-based framework.
Additionally, as artificial intelligence (AI) continues to reshape Medical Affairs, including how MSLs prepare for scientific engagements, analyze insights, and personalize interactions with KOLs, discussions surrounding influential HCPs will likely continue evolving alongside these technological advances 4.
Clearly, findings from both global surveys suggest that the term “Key Opinion Leader” (KOL) remains deeply embedded in the Medical Affairs profession. Despite years of discussion about alternative terminology, KOL remains the preferred term for the majority of Medical Affairs professionals worldwide.
References:
- Medical Science Liaison Society: Global survey on preferred terminology for influential physicians and healthcare professionals. 2017. Available www.themsls.org
- Dyer S J, Shannon E, Kraemer J (April 16, 2026) Perceptions, Utilization, and Impact of Artificial Intelligence on Medical Science Liaisons: A Global Cross-Sectional Survey of Medical Affairs Professionals. Cureus 18(4): e107157. doi:10.7759/cureus.107157
- Dyer S J, Hyder C, Kraemer J, et al. (March 12, 2026) Measuring the Impact of Medical Science Liaisons: A Global Cross-Sectional Survey of Evaluation Practices and Perceptions. Cureus 18(3): e105099. doi:10.7759/cureus.105099
- Dyer S, Hyder C, Kraemer J: Challenges of key performance indicators and metrics for measuring medical science liaison performance: insights from a global survey. Pharmacy (Basel). 2025, 13:51. 10.3390/pharmacy13020051
About the author:
Samuel Dyer, MD, PhD
Dr. Samuel Dyer is the CEO of the Medical Science Liaison Society and has over 26 years of international MSL experience. During his career, he has managed MSL teams and operations in over sixty countries across the United States, Canada, Europe, Africa, the Middle East, Australia, and New Zealand. He has facilitated the successful launch of pharmaceutical and medical device products for both Fortune 500 pharmaceutical companies and small biotechnology companies.
Dr. Dyer has coached, interviewed, and reviewed the CVs of countless aspiring MSLs. His insights and guidance have resulted in hundreds of aspiring MSLs successfully breaking into their first roles.
While leading the MSL Society, he has conducted MSL training programs for over 85 pharmaceutical, biotechnology, and medical device companies in more than 15 countries. Dr. Dyer has also written extensively on the Medical Science Liaison profession, including numerous published articles, benchmark studies, and reports. He has been the keynote speaker and moderated numerous international conferences on various MSL–related topics, including creating teams, management, MSL training, proper utilization of MSLs, global trends, and the KPIs and metrics used to measure MSL performance. Dr. Dyer has also served as a resource and consultant on a number of MSL–related projects for several organizations, including McKinsey & Company and Bain & Company.
Dr. Dyer has an MD from Washington University (Health & Science) School of Medicine, a PhD in Health Sciences from Touro University, a Master’s degree in Tropical Biology (where he studied in the Amazon) from Southern Illinois University Edwardsville, and a Bachelor’s degree in Biology from the University of the State of New York. Dr. Dyer also completed a certificate program for Executive Leadership and Strategy in Pharmaceuticals and Biotechnology at the Harvard Business School.
Dr. Dyer is the author of the multi-award-winning and Amazon #1 Best Seller “The Medical Science Liaison Career Guide: How to Break into Your First Role.” The book is the first and only step-by-step guide on how to break into the MSL career (www.themslbook.com). He is also the author of the Medical Science Liaison Job Application Tracking & Interview Self-Evaluation Journal, which is available on Amazon.
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