Awareness of basic designs for clinical research and of the circumstances in which they are used can aid investigators in obtaining answers to clinical questions. This editorial focuses on designs that can be used by clinicians in their practices, as opposed to designs better suited to laboratory research or the larger arena of epidemiology1 outside the clinical setting.
Table 1 provides an overview of the major clinical study designs and their attributes, including the research questions for which each design is most suited. Special comments relating to each design are provided in Table 2; Table 3 provides examples.
The simplest design is the case report. Recent case reports in the Archives suggest etiologic mechanisms,2 note complications of treatment,3 or report manifestations of a condition that may be helpful in diagnosis.4 Typically, case reports are useful for generating hypotheses that suggest studies involving larger numbers of patients
Daniel Seigel. Designs for Clinical Research. Arch Ophthalmol. 1987;105(12):1647–1649. doi:10.1001/archopht.1987.01060120045019