Number Needed to Teach (N2T2): Bringing Additional Context to the Evaluation of CME Outcomes.

Number needed to treat is a well-established concept in medicine that distils the benefit of a clinical intervention into a single, intuitive value. This paper discusses practical applications of number needed to teach (N2T2), a parallel metric for continuing medical education that quantifies the number of learners who must complete an activity and evaluation for one to achieve a meaningful educational benefit. While the concept has been considered in graduate education of future healthcare professionals, this paper describes the rationale and practical application of N2T2 using a hypothetical example focused on glycaemic status monitoring in type 2 diabetes for CE/CME professionals and participants. By applying pre- and post-activity assessment data to a prespecified improvement threshold, educators can calculate N2T2 to summarise learner gains in knowledge, competence, or performance. Methodological considerations such as paired versus unpaired responses, activity context, learner baseline proficiency and alignment with SMART, Link-SMART and TACT objectives are discussed. It is important to emphasise that N2T2 should be interpreted within the specific context of each activity's goals, audience and outcomes. In the absence of systematic use or established benchmarks for N2T2, early adoption and shared learning within the community are encouraged. N2T2 offers a complementary tool for expressing educational impact clearly and consistently, particularly when applied to longitudinal programmes or multi-activity outcomes. As with number needed to treat in medicine, N2T2 has the potential to bring greater clarity and practicality to how we understand and communicate the value of education. N2T2 is a timely and accessible innovation as we continue to refine educational outcomes measurement together.