It is my understanding (perhaps incorrect) that when running a Markov chain model, unlike a random effects model, it is not necessary to include a term describing the variance-covariance structure of repeated observations obtained from the same experimental unit. 
(1) Is my understanding correct?
(2) If my understanding is correct, why does one not need to adjust for the variance-covariance structure?

Thank you
John  

John David Sorkin M.D., Ph.D.
Professor of Medicine
Chief, Biostatistics and Informatics
University of Maryland School of Medicine Division of Gerontology and Geriatric Medicine
Baltimore VA Medical Center
10 North Greene Street
GRECC (BT/18/GR)
Baltimore, MD 21201-1524
(Phone) 410-605-7119
(Fax) 410-605-7913 (Please call phone number above prior to faxing)


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