observational study

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Related to observational study: experimental study

observational study

A research study in which the results are obtained retrospectively or without a control group. Some examples include case reports, chart reviews, and longitudinal studies of large cohorts followed over time.
Synonym: observational trial
See also: study


a scholarly examination. Specific types of study are also detailed under blind, case-control, cohort, cross-sectional.

analytical study
one in which a phenomenon is described and an attempt made to analyze the effects of variables on the phenomenon.
descriptive study
one in which a phenomenon is described but no attempt is made to analyze the effects of variables on the phenomenon.
follow-up study
one carried out to find out whether there has been change in the situation since the initial study.
longitudinal study
one carried out over a period of time so that chronological time has an opportunity to exert an effect as a variable.
observational study
see descriptive study (above).
prospective study
one in which the data to be studied are yet to be generated, the events having not yet occurred.
retrospective study
one based on examination of existing data, on events that have already occurred.
simulation study
one in which the real circumstances are simulated, either in fact, or by means of a set of mathematical formulae each of which expresses the probability of each outcome in a series of consequential events that mirror the possible pathways in a real-life situation.
References in periodicals archive ?
Homoeopathic treatment of patients with migraine: a prospective observational study with a 2-year follow-up period.
We can see the incidence curve going up starting in year 2 of the observational study.
The current study was conducted after completion of the original observational study in order to assess the degree to which the Hawthorne effect might have influenced the main outcomes measured in this observational study, that is, antibiotic prescribing for viral illnesses and the proportion of cases assigned bacterial diagnoses.
The observational study was carried out as part of the DHA Oxford Learning and Behavior (DOLAB) randomized, placebo-controlled clinical trial, which found increased dietary intake of algal DHA in school-aged children with low reading levels demonstrated significant improvements in reading performance and behavior.
Moreover, the adjusted risk of cardiovascular mortality over the course of a median 5 years of follow-up in this observational study was 36% lower in SSRI-treated patients with PTSD and metabolic syndrome than in those not on an SSRI, and 64% lower in SSRI-treated patients with PTSD without metabolic syndrome.
Spanning 28 countries across 4 continents and involving more than 3300 physicians, A1chieve(R) is set to be the world's largest observational study in insulin therapy.
This observational study is limited in that it does not distinguish between smokers and nonsmokers, and did not check the medical records of those involved," remarks Jose Ramon Banegas, a professor of preventive medicine and public health at the Universidad Autonoma in Madrid, Spain.
Indeed, only 46% of the 8,928 postmenopausal women with stable cardiovascular disease in the Women's Health Initiative (WHI) Observational Study were on aspirin.
A prospective observational study of domestic violence during pregnancy, Obstetrics & Gynecology, 2005, 106(1):61-65.
However, he and his colleagues acknowledge inherent weaknesses in their observational study.
As defined in the Agency for Healthcare Research and Quality (AHRQ) handbook "Registries for Evaluating Patient Outcomes: A User's Guide", a patient registry is "an organized system that uses observational study methods to collect uniform data (clinical and other) to evaluate specified outcomes for a population defined by a particular disease, condition, or exposure, and that serves a predetermined scientific, clinical, or policy purpose(s).
Contrast that with the results of another observational study published in 2011, which found that the mortality rate was significantly higher by 6% in people who took multivitamins than in people who did not take multivitamins.

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