Changes: Study design

Revision as of 07:58, 31 July 2006

Statistics: Scientific method · Research methods · Experimental design · Undergraduate statistics courses · Statistical tests · Game theory · Decision theory

A Study design is a way to set up an epidemiological investigation, as a form of clinical trial.

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.

Experimental

Randomized controlled trial
Nonrandomized controlled trial

Nonexperimental

Cohort study
- Prospective cohort
- Retrospective cohort
- Nested cohort
Case-control (Case series)
- Nested case-control study

Other terms

A "retrospective study" looks at past behavior, while a "prospective study" looks at future behavior.
"Superiority trials" are designed to demonstrate that one treatment is more effective than another.
"Non-inferiority trials" are designed to demonstrate that a treatment is at least not appreciably worse than another.
"Equivalence trials" are designed to demonstrate that one treatment is as effective as another.
When using "parallel groups", each patient receives one treatment; in a "cross-over study", each patient receives several treatment.
A longitudinal study studies a few subjects for a long period of time, while a cross-sectional study involves many subjects measured at once.

External links

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@@ Line 4: / Line 4: @@
 ==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.
+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.
 ===[[Experiment]]al===
 * [[Randomized controlled trial]]
 ** [[Double-blind]]
-** Single-blinded
+** [[Single blind|Single-blind]]
+** [[Open-label trial|Non-blind]]
-** Nonblinded
 * Nonrandomized controlled trial
 ===Nonexperimental===
-*  [[cohort study]]
+*  [[Cohort study]]
 ** Prospective cohort
-** Retrospective cohot
+** Retrospective cohort
 ** Nested cohort
 * [[Case-control]] (Case series)
-** [[nested case-control study]]
+** [[Nested case-control study]]
 ==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.
+* "Superiority trials" are designed to demonstrate that one treatment is more effective than another.
+* "Non-inferiority trials" are designed to demonstrate that a treatment is at least not appreciably worse than another.
-* When using "parallel groups", each patient receives one treatment; in a "cross-over study", each patient receives every treatment.
+* "Equivalence trials" are designed to demonstrate that one treatment is as effective as another.
+* When using "parallel groups", each patient receives one treatment; in a "cross-over study", each patient receives several treatment.
 * A [[longitudinal study]] studies a few subjects for a long period of time, while a [[cross-sectional study]] involves many subjects measured at once.
@@ Line 39: / Line 41: @@
 * [http://imsdd.meb.uni-bonn.de/cancernet/902570.html Comparison of strength]
-{{sci-stub}}
 [[Category:Scientific method]]
 [[Category:Experimental design]]
 {{enWP|Study design}}