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  2. Cohort study - Wikipedia

    en.wikipedia.org/wiki/Cohort_study

    Cohort studies differ from clinical trials in that no intervention, treatment, or exposure is administered to participants in a cohort design; and no control group is defined. Rather, cohort studies are largely about the life histories of segments of populations and the individual people who constitute these segments.

  3. Cohort (statistics) - Wikipedia

    en.wikipedia.org/wiki/Cohort_(statistics)

    Case–control study versus cohort on a timeline. "OR" stands for "odds ratio" and "RR" stands for "relative risk".In statistics, epidemiology, marketing and demography, a cohort is a group of subjects who share a defining characteristic (typically subjects who experienced a common event in a selected time period, such as birth or graduation).

  4. Observational study - Wikipedia

    en.wikipedia.org/wiki/Observational_study

    Cross-sectional study: involves data collection from a population, or a representative subset, at one specific point in time. Longitudinal study: correlational research study that involves repeated observations of the same variables over long periods of time. Cohort study and Panel study are particular forms of longitudinal study.

  5. Clinical study design - Wikipedia

    en.wikipedia.org/wiki/Clinical_study_design

    Randomized controlled trial [5]. Blind trial [6]; Non-blind trial [7]; Adaptive clinical trial [8]. Platform Trials; Nonrandomized trial (quasi-experiment) [9]. Interrupted time series design [10] (measures on a sample or a series of samples from the same population are obtained several times before and after a manipulated event or a naturally occurring event) - considered a type of quasi ...

  6. Research design - Wikipedia

    en.wikipedia.org/wiki/Research_design

    A research design typically outlines the theories and models underlying a project; the research question(s) of a project; a strategy for gathering data and information; and a strategy for producing answers from the data. [1] A strong research design yields valid answers to research questions while weak designs yield unreliable, imprecise or ...

  7. Crossover study - Wikipedia

    en.wikipedia.org/wiki/Crossover_study

    In medicine, a crossover study or crossover trial is a longitudinal study in which subjects receive a sequence of different treatments (or exposures). While crossover studies can be observational studies , many important crossover studies are controlled experiments , which are discussed in this article.

  8. Cohort analysis - Wikipedia

    en.wikipedia.org/wiki/Cohort_analysis

    In cohort analysis, "each new group [cohort] provides the opportunity to start with a fresh set of users," [5] allowing the company to look at only the data that is relevant to the current query and act on it. For example, in eCommerce, customers who signed up in the last two weeks and who made a purchase may constitute a cohort.

  9. Sample size determination - Wikipedia

    en.wikipedia.org/wiki/Sample_size_determination

    The sample size is an important feature of any empirical study in which the goal is to make inferences about a population from a sample. In practice, the sample size used in a study is usually determined based on the cost, time, or convenience of collecting the data, and the need for it to offer sufficient statistical power. In complex studies ...