Generalizability: See applicability and external validity.

GRACE Principles: Acronym for Good Research for Comparative Effectiveness Principles.33, 34 An initiative to enhance the quality of observational comparative effectiveness research and to facilitate its use for decision-making about therapeutic alternatives.

Grey literature: Refers to information that is not published in easily accessible journals or databases.6 Examples include trial registries, conference abstracts, books, dissertations, monographs, and reports held by the Food and Drug Administration and other government agencies, academics, business, and industry.11