[R-sig-ME] Conditional logistic regression vs lmer

[Federico Calboli]

Sorry to dig up an unexciting topic, but the number of random effects in my analysis is increasing so I would like to figure things out. I was trying to compare conditional logistic regression with logistic regression with random terms:

> I am doing a conditional logistic regression with clogit() of library survival, but I have a number of random factors I'd like to add to my model and I was thinking of lmer...
> 
> clg.tigeR = clogit(c.c ~ tIgE.Resp + strata(match), data.ready)
> 
> and all is good. I also have two more variables, both random which I'd like to use, but I am not 100% sure what's the way to go with lmer. I suspect I would need to specify a different intercept for each strata, but seems to baffle me at the moment. The code below might do what I want, but I have no idea if that's correct (i.e. does it match the clogit one + two more random effects?):
> 
> lmer.tigeR = lmer(c.c ~ tIgE.Resp + (tIgE.Resp|match) + (1|Run) + (1|Box), family = binomial, data.ready)
> 
> lmer.tigeR is computed without problems btw.

Most importantly, I utterly fail to see the conceptual difference between *nesting* in a logistic regression with random terms and *strata* in a conditional logistic regression, but that's probably just me.

Best,

F



--
Federico C. F. Calboli
Department of Epidemiology and Biostatistics
Imperial College, St. Mary's Campus
Norfolk Place, London W2 1PG

Tel +44 (0)20 75941602   Fax +44 (0)20 75943193

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