Single Blinding Subjects do not know to which treatment they have been assigned.
Double Blinding Investigators do not know which treatments or evaluation group
the subjects have been assigned.
Gold Standard Refers to diagnostic testing. The patients in the study should
have undergone both the diagnostic test in question such as a blood test, but also the reference (gold)
standard, such as a biopsy or other confirmatory proof that they do or do not have the target disorder.
Systematic Review Minimizes bias in an overview by explicit clinical question,
comprehensive search strategy, clear method of grading the quality of the evidence and clear way of
combining the evidence from individual studies to reach conclusions. Often reviews only clinical trials.
Review (Narrative Review) A Narrative Review includes a process that is
subjective, addresses all aspects of a topic, rather than a single clinical question, and may include all
levels of literature such as letters, case reports, and retrospective studies and book chapters. Reader
does not know the quality of the references included in the review without further investigation.
Metaanalysis A kind of systematic review. Also called data pooling.
Metaanalyses critically review research studies and statistically combine their data to help answer
questions that are beyond the power of single papers. Combining data from a number of studies increases
the sample size. Larger samples mean more precise estimates of rates of risks. Pooling of data from small
clinical trials on the same subject may reveal a clinically important difference in treatments than the
individual small trials lacked the power to detect. Papers as subjects are analyzed.
