Study design

Study design

A study design is an analytic approach to conduct an epidemiological investigation, such as a 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. The ones at the bottom are the most affordable, and are frequently used earlier in the research cycle, to develop strong hypotheses worth testing with the more expensive research approaches.


* Randomized controlled trial
** Double-blind
** Single-blind
** Non-blind
* Nonrandomized controlled trial
*Randomized database studies


* Cohort study
** Prospective cohort
** Retrospective cohort
** Time-trend study
* Case-cohort study
* Case-control study (case series)
** Nested case-control study
* Cross-sectional study


* Community survey

Important considerations

When choosing a study design, many factors must be taken into account. Different types of studies are subject to different types of bias. For example, recall bias is likely to occur in cross-sectional or case-control studies where subjects are asked to recall exposure to risk factors. Subjects with the relevant condition (e.g. breast cancer) may be more likely to recall the relevant exposures that they had undergone (e.g. hormone replacement therapy) than subjects who don't have the condition.

The ecological fallacy may occur when analyses are done on ecological (group-based) data rather than individual data. The nature of this type of analysis tends to overestimate the degree of association between variables.

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 "crossover study", each patient receives several treatments.
* A longitudinal study studies a few subjects for a long period of time, while a cross-sectional study involves many subjects measured at once.

ee also

* Epidemiological methods
* Clinical trial
* Meta-analysis
* Design of experiments
* Experimental control

External links

* [] Epidemiologic Inquiry online weblog for epidemiology researchers
* [ Epidemiology Forum] An epidemiology discussion and forum community to foster debates and collaborations in epidemiology
* [ Some aspects of study design] Tufts University web site
* [ Comparison of strength] Description of study designs from the National Cancer Institute.
* [] Truman State University Political Science Research Design Handbook

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • study design — tyrimo planas statusas T sritis biomedicinos mokslai apibrėžtis Būsimo tyrimo aprašymas, kuriuo nurodomas tikslas bei uždaviniai, kontingentas (↑populiacija), taikomi tyrimo metodai, galimi rezultatai. atitikmenys: angl. study design šaltinis… …   Lithuanian dictionary (lietuvių žodynas)

  • Clinical study design — is the formulation of trials and experiments in medical and epidemiological research, sometimes known as clinical trials. Many of the considerations here are shared under the more general topic of design of experiments but there can be others, in …   Wikipedia

  • Design technology — or DT is the study, design, development, application, implementation, support and management of computer and non computer based technologies for the express purpose of communicating, using various mediums, product design intent and… …   Wikipedia

  • Design of experiments — In general usage, design of experiments (DOE) or experimental design is the design of any information gathering exercises where variation is present, whether under the full control of the experimenter or not. However, in statistics, these terms… …   Wikipedia

  • Design management — is the business side of design. Design managers need to speak the language of the business and the language of design …   Wikipedia

  • Design–build — Design build (or design/build, and abbreviated D–B or D/B accordingly) is a project delivery system used in the construction industry. It is a method to deliver a project in which the design and construction services are contracted by a single… …   Wikipedia

  • Design-based research — (DBR) is a type of research methodology commonly used by researchers in the Learning Sciences. Within Design Based Research methodology, interventions are conceptualized and then implemented in natural settings in order to test the ecological… …   Wikipedia

  • Design thinking — refers to the methods and processes for investigating ill defined problems, acquiring information, analyzing knowledge, and positing solutions in the design and planning fields. As a style of thinking, it is generally considered the ability to… …   Wikipedia

  • Design history — is the study of objects of design in their historical and stylistic contexts. With a broad definition, the contexts of design history include the social, the cultural, the economic, the political, the technical and the aesthetic. Design history… …   Wikipedia

  • Design Exchange — (DX) Established 1994 Location Toronto, Canada Type Museum and Education Centre …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”