longitudinal study


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Related to longitudinal study: Panel study, sequential study

study

 [stud´e]
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.

lon·gi·tu·di·nal stud·y

a study of the natural course of life or disorder in which a cohort of subjects is serially observed over a period of time and no assumptions need be made about the stability of the system.
Synonym(s): diachronic study

longitudinal study

An epidemiologic study that follows a population forward over time, evaluating the effects of one or more variables on a process. If individuals are followed, it is termed a longitudinal cohort study. If classes—e.g., age classes—are studied, it is a longitudinal cross-sectional study. Longitudinal studies are the converse of horizontal studies.
 
Examples
Cohort studies; case-control studies; Framingham Study in Massachusetts, US; Port Pirie study, an ongoing analysis of the long-term effects of blood lead levels on IQ.

longitudinal study

Diachronic study Statistics A study that follows the same persons over time, evaluating the effects of one or more variables on a processtime Examples Cohort studies, case-control studies. Cf Cross-sectional study, Horizontal study.

lon·gi·tu·di·nal stud·y

(lonji-tūdi-năl stŭdē)
A study of the natural course of life or disorder in which a cohort of subjects is serially observed over a period of time and no assumptions need be made about the stability of the system.

longitudinal study

a chronological study in epidemiology which attempts to establish a relationship between an antecedent cause and a subsequent effect. See also cohort study.
References in periodicals archive ?
In the Simmons Longitudinal Study, Reinherz and team members have followed nearly 400 participants from age five to assess developmental milestones and identify mental health problems (Reinherz et al.
A longitudinal study of post-high-school development in gifted individuals at risk for poor educational outcomes.
at the secondary school level--the Education Longitudinal Study of 2002 (ELS:2002) (10th-grade cohort) as well as the earlier National Longitudinal Study of the High School Class of 1972 (NLS:72) (12th-grade cohort), High School and Beyond Longitudinal Study (HS&B) (10th- and 12th-grade cohorts), and National Education Longitudinal Study of 1988 (NELS:88) (8th-grade cohort); and
The longitudinal study involved workers at 10 wood products facilities.
Using panel data from the National Education Longitudinal Study, Long estimates the effect of college quality on a set of early adult outcomes.
People also age at different rates, according to the Baltimore Longitudinal Study on Aging, which has tracked over 1,000 people since 1958.
This book, based on a longitudinal study of the private and social costs associated with smoking, uses stark, simple terms.
During the assent/consent process, each participant was told that the purpose of the longitudinal study was to investigate through the words of the students their life experiences, particularly as they related to the goals of the GEAR UP project (i.
This study used data from the National Educational Longitudinal Study of 1988, This study administered three types of questionnaires per student (student, parent, and teacher).
For example, a cross-sectional study might compare a group of 5 year olds with a group of 6 year olds in 2005, whereas a balanced longitudinal study would test 5 year olds in 2005 and retest those same children in 2006 when they had turned 6 years of age.
While oral sex is most prevalent among white teens, it is young black men between 15 and 17 who report the greatest increase in one longitudinal study, jumping from 25 percent in 1988 to 57 percent in 1995, the last year rates were reported in the National Survey of Adolescent Males.
Based on a review of data from the National Educational Longitudinal Study (NELS: 88), University of California-Los Angeles researchers determined that students who were highly involved in arts instruction earned better grades and performed better on standardized tests.

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