The “half-life” of knowledge: In medicine, as in many sciences, it is shrinking … fast.

What does this mean?

“As change accelerates, something interesting happens … The lifetime value of knowledge rapidly shrinks as the rate of obsolescence in knowledge increases.”

In science, the term “half-life” is the time it takes for a quantity of a substance to reduce itself by one-half. In a 2017 analysis the half-life of medical knowledge was estimated to be about 18–24 months, while it was also projected that the half-life of medical knowledge would collapse to just only 73 days within four years.

What does this mean for CPD professionals, who aim to support HCPs in retaining up-to-date knowledge and skills?

CME/CE is an incredible source for evidence-based, balanced knowledge and skills acquisition for HCPs. And, yet, with the pace of new evidence and the need for knowledge updates, CME/CE must ensure it is hyper-effective in supporting HCPs as they find, access, consume and apply the evidence and strategies for optimized patient care.

As the half-life of knowledge rapidly decreases, HCPs must continuously learn. Technology’s ability to support efficient knowledge transfer has increased, particularly through ubiquitous access to medical data and evidence, AI-supported learning platforms, and the evolution of widely available performance metrics to help drive improvement. Is this enough?

As CPD professionals, we must consider the social context of learners in our work to design and implement CME/CE activities that meet the needs of today’s HCPs. Learners are people who live and move through social environments, which we need to consider for effective learning strategies and their expected impact. Social science literature offers a wealth of insights and frameworks for planning and understanding learning behaviors, which we can apply to the design and implementation of CME/CE.

In foundational writings by Durkheim and elaborated by Granovetter, the theory of social ties has been studied as related to education and offers insights for us related to modern CME/CE. This theory was also recently discussed by Dr. Damon Centola in his Alliance 2025 Annual Conference keynote address. While simple on its face, this proposition offers much that can be applied to our CME/CE plans in practice.

Here’s a brief summary: 

• “Strong ties” are those that develop and are maintained through close relationships between people who interact frequently, share social networks, and offer interpersonal support. This array features family members, close friends, members of social groups and some work colleagues. Examples include a stereotypical family unit as well as the group of six “Friends” from the same-named hit sitcom.
• “Weak ties” are more distant relationships between people who interact infrequently. These connections are varied, heterogenous and offer access to a variety of viewpoints, news and information. These connections occur outside of the close, “strong tie” network. Examples include any of the “extras” that enter the lives of the core “Friends”; they offer new information, challenge accepted thinking, or spur action (and on a sitcom, these are the characters who make shows interesting!).
• When we see change or transformations happen in society, it is most often due to innovations or information moving between individuals and groups who are connected through “weak ties”, where ideas, actions and things are shared across networks. Examples include trends that spread on social media, consumers who are motivated to try new products (and companies) by word-of-mouth affirmations and ideas that spread through discussions among even dissimilar social groups.

So, how do strong and weak ties help us optimize HCP knowledge? How can we help HCPs extend their “half-life” of knowledge? CPD is a valuable mechanism to support HCPs in perpetually renewing their clinical capacity with new information, skills, confidence and motivation to apply evidence in their practice through learning from and with peers and experts. 

With the acceleration of knowledge accessibility, “Stocks of knowledge become progressively less valuable while flows of knowledge — the relationships that can help to generate new knowledge — become more and more valuable.”

Consider how your CME/CE designs leverage relationships across social connections to generate, share and spread new information and practices. The following are potential action steps:

• In live learning, purposefully plan opportunities for social networking among learners to enable new social ties to be forged for the sharing of ideas, information and connections.
• Consider how your CME/CE plan can incorporate peer knowledge sharing to enable participants to learn from each other through shared information and insights, which supports the spread of knowledge across diverse social networks and can increase individuals’ confidence in evaluating new information⁵.
• Select faculty and discussion panel members from a range of institutions and professional backgrounds, to offer new and varying perspectives. This approach advances the professional development of fresh faculty voices — assuming, of course, they hold the requisite expertise and skills to contribute to the learning program.
• Contribute to evolving our community’s understanding of the social drivers to action among HCP learners. For example, in your CME/CE programs, assess HCP learners’ confidence and motivation related to applying knowledge in action. With the resulting data, consider sharing presentations or papers with the Alliance community to further our collective understanding of the relationship among HCP knowledge, behaviors and social mediators for taking action.

In summary, in your CPD plans, consider how you can apply effective strategies and learnings from social science literature to ensure your CME/CE program is optimally aiding HCPs’ access to new information, and develop the skills and confidence to apply it in real-world practice.

This article is intended as the first in a series exploring practical applications of social science theory and frameworks for CPD design and implementation to collectively broaden our shared understanding.

References

Hagel, J III & Brown, JS (2006). Creation nets: Harnessing the potential of open innovation. Accessed January 20, 2025 at https://www.johnhagel.com/creationnets.pdf

Sepulveda, MJ. (2017) Commentary on talk, “Does it Really Matter? Cognitive Technologies, Thinking and Time.” Accessed January 20, 2025 at https://hms.harvard.edu/news/medicine-changing-world

Durkheim, E. (1893). The Division of Labour in Society. New York: The Free Press.

Granovetter, MS (1973). The Strength of Weak Ties. American Journal of Sociology, 78(6), 1360–1380.

Centola, D., Becker, J., Zhang, J., Aysola, J., Guilbeault, D., & Khoong, E. (2023). Experimental evidence for structured information–sharing networks reducing medical errors. Proceedings of the National Academy of Sciences (PNAS), 120(31).

Caroline O. Pardo, PhD, CHCP, FACEHP, is the founder of Table Talk on Health and a consulting advisor for IAS LLC. She is a thought leader in human-centered and healthcare professional and patient interventions to improve outcomes, with specialized expertise in the application of clinical, social science and research methodology to the design, execution and evaluation of comprehensive education, training and implementation science initiatives.