Swimming in the Sea of Real-World Evidence (RWE) Guidance: Why More Guidance Documents Are Needed to Help Researchers Swim.

Real-world evidence (RWE) plays an expanding role in regulatory, health technology assessment (HTA), and lifecycle decision-making, prompting a rapid increase in guidance documents intended to support its generation and use. This commentary argues that additional guidance is not redundant; rather, it is necessary to sustain consistency, credibility, and confidence as RWE methods become more specialized and operationally complex. Recent advances, including pragmatic and registry-based trials, hybrid randomized-real-world designs, external control arms, artificial intelligence and machine learning applications, digital health data, synthetic controls, and data tokenization, have outpaced the scope of many existing frameworks. Although recent reporting initiatives and international harmonization efforts have improved transparency and reproducibility, important gaps remain in implementation-focused guidance on issues such as causal inference, dynamic borrowing, linkage validation, algorithm auditability, reproducibility, and distributed data environments. The need is further amplified by heterogeneity across regulatory and HTA agencies, where differing evidentiary expectations can create uncertainty and inefficiency, and by the limited availability of context-appropriate guidance for low- and middle-income countries, where structural data and infrastructure constraints may hinder RWE generation and use. Future progress should emphasize targeted, modular, and potentially "living" guidance that is updated as methods evolve, while also improving uptake of existing frameworks through clearer reporting expectations, education, and stakeholder collaboration. More guidance, when focused and implementation-oriented, can better translate methodological principles into decision-grade RWE.