BibTeX
@MISC{Therneau11thelmekin,
author = {Terry Therneau},
title = {The lmekin function},
year = {2011}
}
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Abstract
The original kinship library had an implementation of linear mixed effects models using the matrix code found in coxme. Since the primary motivation for the functions in that library was to fit models with random family effects, i.e., using a kinship matrix for the correlation, the name lmekin was chosen. The reason for the program was entirely to check our arithmetic: the result of the matrix manipulations contained in it should give exactly the same answer as lme, and since the underlying routines were shared with coxme that gave a validity check for parts of coxme. With more time and a larger test suite the routine is no longer necessary for this purpose, however, it became popular with users (they often do unanticipated things) since it can fit a few models that lme cannot. Let me emphasis this: most models that can be fit with the lmekin function can also be fit with lme and/or lmer. For any such model the lme/lmer functions will be faster and have superior support routines (residuals, printing, plotting, etc.) The solution code for lmer is likely also more reliable since it has been exercised on a much wider variety of data sets. However, there are models that lmekin will fit which lme will not. The most obvious of these are models with a random genetic effect, e.g. a kinship matrix. The second class will be models
Keyphrases
lmekin function kinship matrix name lmekin second class underlying routine original kinship library matrix manipulation test suite solution code validity check random family effect matrix code data set unanticipated thing random genetic effect linear mixed effect model primary motivation lme lmer function superior support routine lme cannot fit model
