Improving power in small-sample longitudinal studies when using generalized estimating equations
نویسندگان
چکیده
منابع مشابه
Small-sample adjustments in using the sandwich variance estimator in generalized estimating equations.
The generalized estimating equation (GEE) approach is widely used in regression analyses with correlated response data. Under mild conditions, the resulting regression coefficient estimator is consistent and asymptotically normal with its variance being consistently estimated by the so-called sandwich estimator. Statistical inference is thus accomplished by using the asymptotic Wald chi-squared...
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The generalized estimating equation (GEE) approach of Zeger and Liang facilitates analysis of data collected in longitudinal, nested, or repeated measures designs. GEEs use the generalized linear model to estimate more efficient and unbiased regression parameters relative to ordinary least squares regression in part because they permit specification of a working correlation matrix that accounts...
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Background & Objective: Pain is a common symptom among people with MS. In the majority of MS patients, pain is chronic in nature, but it can change over time. The objective of this study was to determine if pain type can predict pain severity changes in individuals with MS over time. Materials & Methods: The research method was a longitudinal design that evaluated pain type and severity at...
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The robust or sandwich estimator is common to estimate the covariance matrix of the estimated regression parameter for generalized estimating equation (GEE) method to analyze longitudinal data. However, the robust estimator would underestimate the variance under a small sample size. We propose an alternative covariance estimator to the robust estimator to improve the small-sample bias in the GE...
متن کاملPower and Sample Size Calculations for Generalized Estimating Equations via Local Asymptotics.
We consider the problem of calculating power and sample size for tests based on generalized estimating equations (GEE), that arise in studies involving clustered or correlated data (e.g., longitudinal studies and sibling studies). Previous approaches approximate the power of such tests using the asymptotic behavior of the test statistics under fixed alternatives. We develop a more accurate appr...
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ژورنال
عنوان ژورنال: Statistics in Medicine
سال: 2016
ISSN: 0277-6715
DOI: 10.1002/sim.6967