Identifies, appraises and synthesizes all [quality] empirical evidence that meets pre-specified eligibility
Clinical practice guidelines are systematically developed statements to assist practitioner and patient decisions about appropriate health care for specific clinical circumstances.” (Institute of Medicine, 1990)
Systems -patient-specific, evidence-based, computerized decision support
Evidence Summaries - summaries of evidence for decision making; includes comprehensive information for common clinical topics
Randomised Controlled Trial - clinical study in which subjects are randomly assigned to groups; one group is the experimental intervention and other(s) is the control (alternative or placebo). Provides indication of effectiveness.
Cohort Study - observational study that follows a group and looks at differences in outcome of interest within the group. Retrospective studies look at suspected risk factor (causation). Prospective studies track risk factor or outcome of interest; very difficult to control for all variables
Case Control - observational study that matches a group based on a common condition or exposure and compares them to a group without the condition or exposure; may show correlation but not necessarily causation.
Cross-sectional Study - descriptive study the measures prevalence or determinants of health in a specific population in a given time frame; used to explore or propose explanation for health-related issue
Case Series - a set of cases from clinicians that are all related to a specific disease or issue; may lead to subsequent clinical trials
Case Reports - one report related to a specific health issue of an individual patient
Figure 1 shows the tree of possible designs, branching into subgroups of study designs by whether the studies are descriptive or analytic and by whether the analytic studies are experimental or observational. The list is not completely exhaustive but covers most basics designs.