Describing Research Design

This article explains how the research design of a study can simultaneously be described in many different ways as nonempirical or empirical, case-based or sample-based, observational or interventional, retrospective or prospective, cross-sectional or longitudinal, uncontrolled or controlled, single arm or multiple arm, nonrandomized or randomized, crossover or parallel group, nonblind, single-blind, or double-blind, superiority or noninferiority, exploratory (hypothesis generating) or confirmatory (hypothesis driven), and many others. Some of these categories can be associated with special types of research design as well, such as cohort studies, case-control studies, nested case-control studies, wedge design studies, and so on. Readers should understand which descriptors are mutually exclusive and which are not.