A Study design is a way to set up an epidemiological investigation, as a form of clinical trial. Epidemiology (Greek epi = upon, among; demos = people, district; logos = word, discourse), defined literally, is the study of epidemics in humans. ... Jump to: navigation, search In medicine, a clinical trial (synonyms: clinical studies, research protocols, medical research) is a research study. ...

Types of design

Some of the most popular designs are sorted below, with the ones at the top being the most powerful at reducing Observer-expectancy effect (but also most expensive, and in some cases introducing ethical concerns) and the ones at the bottom being the most affordable. Frequently the ones at the bottom are used earlier in the research cycle, to develop strong hypotheses worth testing with the more expensive research approaches. The observer-expectancy effect, in science, is a cognitive bias that occurs in science when a researcher expects a given result and therefore unconsciously manipulates an experiment or misinterprets data in order to find it. ...

Experimental

• Randomized controlled trial
  • Double-blind
  • Single-blinded
  • Nonblinded
• Nonrandomized controlled trial

Jump to: navigation, search From Latin ex- + -periri (akin to periculum attempt). ... Jump to: navigation, search A randomized contro // Headline text lInsert non-formatted text hereled trial (RCT) is a form of clinical trial, or scientific procedure used in the testing of the efficacy of == medicines oBold textreliable form of scientific evidence because [[ == it is the best known designr... Double-blind describes an especially stringent way of conducting an experiment, usually on living, conscious, human subjects. ...

Nonexperimental

• cohort study
  • Prospective cohort
  • Retrospective cohot
• Case-control (Case series)
  • nested case-control study

It has been suggested that this article or section be merged with Cohort (statistics). ... Case-control studies are one type of epidemiological study design. ...

Other terms

• A "retrospective study" looks at past behavior, while a "prospective study" looks at future behavior.
• "Equivalence trials" are designed to demonstrate that one treatment is as effective as another, while "superiority trials" are designed to demonstrate that one treatment is more effective than another.
• When using "parallel groups", each patient receives one treatment; in a "cross-over study", each patient receives every treatment.
• A longitudinal study studies a few subjects a long period of time, while a cross-sectional study involves many subjects measured at once.

Longitudinal studies form a class of research methods that involve observations of the same items over a longer time. ... Cross-sectional studies form a class of research methods that involve observation of some subset of a population of items all at the same time. ...

See also

• Epidemiological methods
• Clinical trial
• recall bias
• Meta-analysis
• Design of experiments
• Experimental control

Readers not making a formal study of epidemiology will often see the names of epidemiological methods quoted without reference to their actual definition. ... Jump to: navigation, search In medicine, a clinical trial (synonyms: clinical studies, research protocols, medical research) is a research study. ... Taken generally, recall bias occurs when the way a survey respondent answers a question is affected not just by the correct answer, but also by the respondents memory. ... A meta-analysis is a statistical practice of combining the results of a number of studies. ... The first statistician to consider a methodology for the design of experiments was Sir Ronald A. Fisher. ... Experimental controls are used in all accurate scientific experiments. ...

External links

• Tufts
• Comparison of strength