Table 2.

Preliminary data items to extract from regulatory guidelines, viewpoints, expert group recommendations, and other similar sources.

Data items			Explanation
Publication details
	Authors and reference	Who wrote the paper? Include the reference.
	Year	When was the paper published?
	Type of source	In what type of literature was the paper published (journal, conference, gray literature—conference, thesis or dissertation, clinical trials registry platform, white paper, academic and industry report, opinion paper, blog or website or forum post, letter, guideline, book chapter, editorial, commentary, paper or guideline by expert group, regulatory entity, or others)?
	Country or region	In which country or region was the paper written? To which regions do the recommendations apply (which country or region, global)?
General details
	Sampling size	What is the recommended or used sample size?
	Sampling method	What method is recommended or used for sampling?
	Study design	What study design is recommended or used for clinical validation?
Digital endpoint details
	Clinical application of digital endpoints	What is the clinical application of digital endpoints (diagnostic, safety, response, monitoring, prognostic, risk, or predictive)?
	Type of validation methods	Which type of validation method is recommended? The trial, simulation, expert opinion, model-centered, and other?
	Analytical methods	What methods are recommended to measure the relationship between clinically relevant outcomes and digital endpoints? What association measures should be used?
	Analytical methods	Is there any consideration for using the digital endpoint as a primary, secondary, or exploratory endpoint?