PubMed Health⌕ Search

PubMed · 1480875

Computational aspects of analysing random effects/longitudinal models.

Abstract

Random effects and longitudinal models are becoming increasingly popular in the analysis of many types of data, including medical and biopharmaceutical, because of their richness and flexibility. They can be, however, difficult to fit using traditional statistical tools. Fortunately, there now exists a burgeoning collection of newer computational methods that can be applied to draw inferences with such models. This review attempts to provide an introduction to some of these techniques by describing them as extensions of the EM algorithm, currently a standard tool for the analysis of longitudinal and random effects models. For clarity of exposition, the extensions are classified into three types: large-sample iterative; large-sample simulation, and small-sample simulation.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

D B Rubin. Computational aspects of analysing random effects/longitudinal models.. https://doi.org/10.1002/sim.4780111405

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Latent variable models for longitudinal data with multiple continuous outcomes.

Multiple outcomes are often used to properly characterize an effect of interest. This paper proposes a latent variable model for the situation where repeated measures over time are obtained on each outcome. These outcomes are assumed to measure an underlying quantity of main interest from different perspectives. We relate the observed outcomes using regression models to a latent variable, which is then modeled as a function of covariates by a separate regression model. Random effects are used to model the correlation due to repeated measures of the observed outcomes and the latent variable. An EM algorithm is developed to obtain maximum likelihood estimates of model parameters. Unit-specific predictions of the latent variables are also calculated. This method is illustrated using data from a national panel study on changes in methadone treatment practices.

Longitudinal Studies↗

[Thematic and methodological analysis of investigation in primary care (1988-1992)].

OBJECTIVE: To describe Spanish scientific output in primary care with regard to subjects, design and statistical methods employed and also its appropriateness, importance and funding. DESIGN: Descriptive, longitudinal and retrospective study. SETTING: Spanish scientific output in primary care published in medical journals and listed in the Indice Medico Español during the five year period 1988-1992. MATERIAL: 446 original articles published in thirty-four journals. MEASUREMENTS AND MAIN RESULTS: The greatest percentage of articles came under the heading "policy and health" (23.6%), next was "health services" (14.8%). There was a predominance of observational designs (79.9%) and within this category, descriptive studies (67.1%). The most common statistical methods used were contingency tables (35,9%). The majority of articles (94.8%) do not indicate the source of their funding. The appropriateness was around 50% and the importance around 4%. CONCLUSIONS: According to our study, research into primary care centres on the evaluation and organization of the health services. The majority of the designs have little inferential power and simple statistical methods. There is hardly any funding available, and only a half of the articles comply with appropriateness criteria.

Longitudinal Studies↗

New contributions to the ethnopharmacology of Spain.

In the course of an ethnobotanical research project carried out in the Province of Granada (Southern Spain), 267 taxa have been catalogued as being used in folk medicine. Based on the literature consulted, phytotherapeutic use for 34 of these was recorded for the first time.

Longitudinal Studies↗