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lollywolly
Calcite | Level 5

Hi All,

 

I am trying to pre-specify / get a better understanding of how to perform a multivariate (3 or 4 outcomes) longitudinal repeated measures analysis where outcomes are measured daily over many months

 

If I had just a few time points then my research has guided me towards a random coefficient models in PROC MIXED such as that specified in “Analyzing Multivariate Longitudinal Data Using SAS® “.

 

But I am struggling to find details of models to account for "continuous" time.  I have seen mention of modelling time as a continuous variable, or the use of a splined covariance structure.  Would someone mind pointing me in the direction of some appropriate literature in relation to these, or other suggested methodologies please.

 

Thank you.

2 REPLIES 2
pau13rown
Lapis Lazuli | Level 10

time is continuous in the random coefficients model that you mention. You might want to look at brown and prescott's book: https://onlinelibrary.wiley.com/doi/book/10.1002/9781118778210

 

i'm pretty sure they cover SAS (ie give code examples) and discuss random coefficient models and building a polynomial model for nonlinear relationship with time. Although, im not sure if they discuss the multivariate case

lollywolly
Calcite | Level 5

Great thank you so much for your reply and guidance  ... I will be looking at the book right away :).  

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