Module 1-1 – Explanatory vs Pragmatic Trials (10-min video).

• Summary: This introductory module outlines the key distinctions between explanatory and pragmatic clinical trials, setting the stage for the design of pragmatic trials. It explores these differences through core elements, including participant selection, intervention flexibility, study setting, and outcome measurement. Learners are introduced to the PRECIS-2 wheel, a visual tool that evaluates the pragmatic nature of trials across multiple domains, guiding researchers to align their design decisions with the trial’s intended goals. A central theme of the module is understanding the balance between internal validity and external validity. Learners are encouraged to view trial designs not as strictly explanatory or pragmatic, but as existing along a continuum that reflects real-world complexity. 

** The content, slides, and narrator's voice were generated with the assistance of artificial intelligence, with human guidance and oversight throughout the process.

Loudon et al. The PRECIS-2 tool: designing trials that are fit for purpose. BMJ. 2015;350:h2147. doi:10.1136/bmj.h2147. (11-page paper)

• The PRECIS-2 tool helps researchers design clinical trials that align with their purpose, whether they aim to test whether an intervention works under ideal conditions (explanatory trials) or in real-world settings (pragmatic trials). PRECIS-2 guides trialists across nine key domains: eligibility criteria, recruitment, setting, organisation, flexibility in delivery and adherence, follow-up, primary outcome, and primary analysis. Each domain is rated from 1 (very explanatory) to 5 (very pragmatic), using a wheel diagram for visualization. The PRECIS-2 encourages trial teams to make deliberate, transparent design choices that reflect how they intend the results to be used.