Veterinary - Evidence-Based Veterinary Medicine

Typically refers to a method of synthesis of quantitative data from multiple independent studies addressing a common research question. A statistical technique that summarizes the results of several studies in a single weighted estimate, in which more weight is given to results of studies with more events and sometimes to studies of higher quality. 

A review that involves systematically identifying, selecting, and analyzing all available studies related to a clearly formulated question. A comprehensive literature search is performed, and practice recommendations based on the well-done studies are involved.

Provides a quick and succinct assessment of what is known (and not known) in the scientific literature about an intervention or practical issue by using a systematic methodology to search and critically appraise primary studies. However, in order to be quick, a CAT makes concessions in relation to the breadth, depth and comprehensiveness of the search. Due to these limitations, a CAT is more prone to selection bias than a systematic review or rapid evidence assessment. 

A trial in which participants are randomly assigned to two or more groups: at least one (the experimental group) receiving an intervention that is being tested and another (the comparison or control group) receiving an alternative treatment or placebo. This design allows an assessment of the relative effects of interventions and helps reduce bias as randomization balances participant characteristics (both observed and unobserved) between the groups allowing attribution of any differences in outcome to the study intervention.

A non-experimental study design that follows a group of people (a cohort), and then looks at how events differ among people within the group. A study that examines a cohort, which differs in respect to exposure to some suspected risk factor (e.g., smoking), is useful for trying to ascertain whether exposure is likely to cause specified events (e.g., lung cancer). Prospective cohort studies (which track participants forward in time) are more reliable than retrospective cohort studies.

A study design that examines a group of people who have experienced an event (usually an adverse event) and a group of people who have not experienced the same event, and looks at how exposure to suspect (usually noxious) agents differed between the two groups. This type of study design is most useful for trying to ascertain the cause of rare events, such as rare cancers. Case-control studies can only generate odds ratios (OR) and not a relative risk (RR). Case-control studies provide weaker evidence than cohort studies but are more reliable than case series.

Analysis of a series of people with the disease (there is no comparison group in case series). Case series provide weaker evidence than case-control studies.

Definitions from BMJ's Glossary of EBM Terms