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Nested Case–control Study
A nested case–control (NCC) study is a variation of a case–control study in which cases and controls are drawn from the population in a fully enumerated cohort. Usually, the exposure of interest is only measured among the cases and the selected controls. Thus the nested case–control study is more efficient than the full cohort design. The nested case–control study can be analyzed using methods for missing covariates. The NCC design is often used when the exposure of interest is difficult or expensive to obtain and when the outcome is rare. By utilizing data previously collected from a large cohort study, the time and cost of beginning a new case–control study is avoided. By only measuring the covariate in as many participants as necessary, the cost and effort of exposure assessment is reduced. This benefit is pronounced when the covariate of interest is biological, since assessments such as gene expression profiling are expensive, and because the quantity of blood availabl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nurses' Health Study
The Nurses Health Study is a series of prospective studies that examine epidemiology and the long-term effects of nutrition, hormones, environment, and nurses' work-life on health and disease development. The studies have been among the largest investigations into risk factors for major chronic diseases ever conducted. The Nurses' Health Studies have led to many insights on health and well-being, including cancer prevention, cardiovascular disease, and type 2 diabetes. They have included clinicians, epidemiologists, and statisticians at the Channing Laboratory (of Brigham and Women's Hospital), Harvard Medical School, Harvard School of Public Health, and several Harvard-affiliated hospitals, including Brigham and Women's Hospital, Dana–Farber Cancer Institute, Children's Hospital Boston, and Beth Israel Deaconess Medical Center. Cohorts The Nurses' Health Study original cohort was established in 1976 by Frank E. Speizer. Initially, the study investigated contraceptive us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Expression
Gene expression is the process (including its Regulation of gene expression, regulation) by which information from a gene is used in the synthesis of a functional gene product that enables it to produce end products, proteins or non-coding RNA, and ultimately affect a phenotype. These products are often proteins, but in non-protein-coding genes such as Transfer RNA, transfer RNA (tRNA) and Small nuclear RNA, small nuclear RNA (snRNA), the product is a functional List of RNAs, non-coding RNA. The process of gene expression is used by all known life—eukaryotes (including multicellular organisms), prokaryotes (bacteria and archaea), and viruses—to generate the macromolecule, macromolecular machinery for life. In genetics, gene expression is the most fundamental level at which the genotype gives rise to the phenotype, ''i.e.'' observable trait. The genetic information stored in DNA represents the genotype, whereas the phenotype results from the "interpretation" of that informati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conditional Logistic Regression
Conditional logistic regression is an extension of logistic regression that allows one to account for stratification and matching. Its main field of application is observational studies and in particular epidemiology. It was devised in 1978 by Norman Breslow, Nicholas Day, Katherine Halvorsen, Ross L. Prentice and C. Sabai. It is the most flexible and general procedure for matched data. Background Observational studies use stratification or matching as a way to control for confounding. Logistic regression can account for stratification by having a different constant term for each stratum. Let us denote Y_\in\ the label (e.g. case status) of the \ellth observation of the ith stratum and X_\in\mathbb^p the values of the corresponding predictors. We then take the likelihood of one observation to be : \mathbb(Y_=1, X_)=\frac where \alpha_i is the constant term for the ith stratum. The parameters in this model can be estimated using maximum likelihood estimation. For exampl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annals Of Statistics
The ''Annals of Statistics'' is a peer-reviewed statistics journal published by the Institute of Mathematical Statistics. It was started in 1973 as a continuation in part of the '' Annals of Mathematical Statistics (1930)'', which was split into the ''Annals of Statistics'' and the '' Annals of Probability''. The journal CiteScore is 5.8, and its SCImago Journal Rank is 5.877, both from 2020. Articles older than 3 years are available on JSTOR, and all articles since 2004 are freely available on the arXiv arXiv (pronounced as "archive"—the X represents the Chi (letter), Greek letter chi ⟨χ⟩) is an open-access repository of electronic preprints and postprints (known as e-prints) approved for posting after moderation, but not Scholarly pee .... Editorial board The following persons have been editors of the journal: * Ingram Olkin (1972–1973) * I. Richard Savage (1974–1976) * Rupert G. Miller (1977–1979) * David V. Hinkley (1980–1982) * Michael D. Perlm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inverse Probability Weighting
Inverse probability weighting is a statistical technique for estimating quantities related to a population other than the one from which the data was collected. Study designs with a disparate sampling population and population of target inference (target population) are common in application. There may be prohibitive factors barring researchers from directly sampling from the target population such as cost, time, or ethical concerns. A solution to this problem is to use an alternate design strategy, e.g. stratified sampling. Weighting, when correctly applied, can potentially improve the efficiency and reduce the bias of unweighted estimators. One very early weighted estimator is the Horvitz–Thompson estimator of the mean. When the sampling probability is known, from which the sampling population is drawn from the target population, then the inverse of this probability is used to weight the observations. This approach has been generalized to many aspects of statistics under vario ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidemiological Study Projects
Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and determinants of health and disease conditions in a defined population, and application of this knowledge to prevent diseases. It is a cornerstone of public health, and shapes policy decisions and evidence-based practice by identifying risk factors for disease and targets for preventive healthcare. Epidemiologists help with study design, collection, and statistical analysis of data, amend interpretation and dissemination of results (including peer review and occasional systematic review). Epidemiology has helped develop methodology used in clinical research, public health studies, and, to a lesser extent, basic research in the biological sciences. Major areas of epidemiological study include disease causation, transmission, outbreak investigation, disease surveillance, environmental epidemiology, forensic epidemiology, occupational epidemiology, screening, biomonitoring, and comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Design Of Experiments
The design of experiments (DOE), also known as experiment design or experimental design, is the design of any task that aims to describe and explain the variation of information under conditions that are hypothesized to reflect the variation. The term is generally associated with experiments in which the design introduces conditions that directly affect the variation, but may also refer to the design of quasi-experiments, in which natural conditions that influence the variation are selected for observation. In its simplest form, an experiment aims at predicting the outcome by introducing a change of the preconditions, which is represented by one or more independent variables, also referred to as "input variables" or "predictor variables." The change in one or more independent variables is generally hypothesized to result in a change in one or more dependent variables, also referred to as "output variables" or "response variables." The experimental design may also identify ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cohort Study Methods
Cohort or cohortes may refer to: Cohort Sociological * Cohort (military unit), the basic tactical unit of a Roman legion * Cohort (educational group), a group of students working together through the same academic curriculum Scientific * Cohort (statistics), a group of subjects with a common defining characteristic, for example age group * Cohort (floating point), a set of different encodings of the same numerical value * Cohort (taxonomy), in biology, one of the taxonomic ranks * Cohort study, a form of longitudinal study used in medicine and social science * Cohort analysis, a subset of behavioral analytics that takes the data from a given data set * Generational cohort, an aggregation of individuals who experience the same event within the same time interval Gaming * Cohort Studios, a video game development company * "Cohort", a disc golf putter by Infinite Discs Cohortes * ''Cohortes urbanae The ''cohortes urbanae'' (Latin meaning ''urban cohorts'') of ancient Rome ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
