[R-sig-ME] logistic model with exponential decay

David Duffy David.Duffy at qimr.edu.au
Sun Dec 21 22:03:46 CET 2008

On Sun, 21 Dec 2008, Stijn Ruiter wrote:

> Hi,
> I have official judicial data on criminal offending (dichotomous dependent 
> variable=conviction(=Y)) of all (adult) children of fathers who differ with 
> respect to their level of criminal behavior. These data were registered on a 
> yearly basis. So, I am able to follow people over the course of their lives 
> and model whether they get convicted. I intend to estimate a discrete-time 
> logit model on a person-year file. Of course, because children are nested 
> within their fathers, I need to take that into account. Furthermore, many 
> subjects get convicted more than once during their lives, so I need to 
> estimate a repeated events model.
> I have several time-constant variables (e.g., gender) and several 
> time-varying variables (e.g., number of years since father committed a 
> crime(=T)). I would like to estimate something like this:
> logit(Y) ~ alpha + beta1*GENDER + exp(-T/beta2) + ... + error term for 
> nesting within fathers + error term for nesting within subject

You also want the person-years at risk as an offset too, don't you?  And 
do you have many families, so there are multiple individuals with the same 
father?  You may know that the R survival package implements frailty 
models that would be applicable, and that the kinship package specifically 
offers a Cox proportional hazards model (with gaussian random effects) 
that can incorporate two crossed variance components.

Cheers, David Duffy.

| David Duffy (MBBS PhD)                                         ,-_|\
| email: davidD at qimr.edu.au  ph: INT+61+7+3362-0217 fax: -0101  /     *
| Epidemiology Unit, Queensland Institute of Medical Research   \_,-._/
| 300 Herston Rd, Brisbane, Queensland 4029, Australia  GPG 4D0B994A v

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