cohort study

(redirected from incidence study)


a careful examination of a phenomenon; see also design.
cohort study prospective study.
cross-sectional study one employing a single point of data collection for each participant or system being studied. It is used for examining phenomena expected to remain static through the period of interest. It contrasts with a longitudinal s.
electrophysiological s's (EPS) studies from within the heart of its electrical activation and response to electrical stimuli and certain drugs. In general they include intravenous and/or intra-arterial placement of one or more electrode catheters at sites in the atria, ventricles, or coronary sinus, and sometimes the pulmonary artery or aorta. They record activity or stimulate the heart at various rates and cadences and are aids in the evaluation of electrophysiologic properties such as automaticity, conduction, and refractoriness. They also initiate and terminate tachycardias, map the sequence of activation, and aid in evaluation of patients for various forms of therapy and for the response to therapy. During these studies catheter ablation procedures, such as radio frequency ablation and electrical ablation, may be performed.
flow study uroflowmetry.
longitudinal study one in which participants, processes, or systems are studied over time, with data being collected at multiple intervals. The two main types are prospective studies and retrospective studies. It contrasts with a cross-sectional s.
pilot study a smaller version of a proposed research study, conducted to refine the methodology of the later one. It should be as similar to the proposed study as possible, using similar subjects, the same setting, and the same techniques of data collection and analysis.
prospective study an epidemiologic study in which the groups of individuals (cohorts) are selected on the bases of factors that are to be examined for possible effects on some outcome. For example, the effect of exposure to a specific risk factor on the eventual development of a particular disease can be studied. The cohorts are then followed over a period of time to determine the incidence rates of the outcomes being studied as they relate to the original factors in question. Called also cohort study.

The term prospective usually implies a cohort selected in the present and followed into the future, but this method can also be applied to existing longitudinal historical data, such as insurance or medical records. A cohort is identified and classified as to exposure to the risk factor at some date in the past and followed up to the present to determine incidence rates. This is called a historical prospective study, prospective study of past data, or retrospective cohort study.
retrospective study an epidemiologic study in which participating individuals are classified as either having some outcome (cases) or lacking it (controls); the outcome may be a specific disease, and the persons' histories are examined for specific factors that might be associated with that outcome. Cases and controls are often matched with respect to certain demographic or other variables but need not be. As compared to prospective studies, retrospective studies suffer from drawbacks: certain important statistics cannot be measured, and large biases may be introduced both in the selection of controls and in the recall of past exposure to risk factors. The advantage of the retrospective study is its small scale, usually short time for completion, and its applicability to rare diseases, which would require study of very large cohorts in prospective studies. See also prospective s.
urinary flow study uroflowmetry.
voiding pressure study simultaneous measurement of bladder contraction, urinary flow, and sphincter electromyogram.

co·hort stud·y

a study using epidemiologic methods, such as a clinical trial, in which a cohort with a particular attribute (for example, smokers, recipients of a drug) is followed prospectively and compared for some outcome (for example, disease, cure) with another cohort that does not possess that attribute.
Synonym(s): follow-up study (1)

cohort study

(in research) a study concerning a specific subpopulation, such as the children born between December and May in 1975 or those born in the same months in 1955. See also prospective study.

cohort study

An observational study in which a defined group of people (a cohort) is followed over time and outcomes are compared in subsets of the cohort who were exposed, not exposed, or exposed at different levels to an intervention or other factor of interest. Cohorts can be assembled in the present and followed into the future (a “concurrent cohort study”), or identified from past records and followed from that time up to the present (a “historical cohort study”). Because random allocation is not used, matching or statistical adjustment must be used to ensure that the comparison groups are as similar as possible.
References in periodicals archive ?
In addition, data from the 2008 Canadian Incidence Study of Reported Child Abuse and Neglect, which is a cross-Canada study of child protection agencies' child maltreatment investigations, are available to researchers and student researchers for secondary analyses (child.
retrospective bladder cancer incidence study, 385 of 532 workers ever exposed to MBOCA from 1968 to 1979 and 20 workers who were first employed in 1980 and 1981 participated in a urine screening test (Ward et al.
The research, which compared the 1998 Ontario Incidence Study of Reported Child Abuse and Neglect with a 1993 incidence study, also found an 870 per cent increase in cases of substantiated emotional maltreatment, largely as a result of exposure to domestic violence.
Apart from the recent Canadian Incidence Study of Reported Child Abuse and Neglect (CIS) (see next section), many of these estimates are out of date (e.
A Scandinavian cancer incidence study evaluated 6,222 women with breast implants including 3,336 women with 15 or more years of follow-up and 827 with 25 or more years of follow-up and found no excess of lymphoma in subjects with implants (Lipworth, Jan 2009).
Table 1 shows the findings of a hypothetical incidence study of 20,000 persons followed for 10 years (Pearce 2003).
The gerontology and sociology researchers are seeking funding to conduct a national-level incidence study of cases of missing seniors with dementia, as well as regional funding to study the problem in the southwestern Ohio region.
Defendants did not challenge the first Daubert criterion, and the judge found that "the cancer incidence study methodology consists of a testable hypothesis" (TMI Litigation Cases Consolidated II 1996a).
Ranked number one (84%) in Total Brand Awareness by the Bubble Gum Incidence Study, October 2004, the gum was also included in a psychological study of tastes and smells that recall memories.
Based on information in the department's Tax Incidence Study, the average sales tax paid was estimated by income level and is the basis for the sales tax rebate.
The first four phases of the health investigation included a case series study, a site-wide cancer incidence study, a site-wide mortality study and a 500 building complex cancer and tumor incidence survey.
According to the "Minnesota Tax Incidence Study," Minnesota's personal income tax is significantly progressive.