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Re: st: analysis of cluster of fungal infection in an ICU-unit


From   Austin Nichols <austinnichols@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: analysis of cluster of fungal infection in an ICU-unit
Date   Thu, 22 Dec 2011 15:56:37 -0500

roland andersson <rolandersson@gmail.com>:

I meant that if you just want a test of whether a given type of
infection is more likely after the same type, which you have already
said you observed in a graph, you could run a simple mlogit.  No
infection could also be a category modeled, and you could include all
the negative results.

For example, here is a case where the null is true (no clustering
implied by the DGP):

clear
range id 1 1000 1000
g type=ceil(uniform()*6)
tsset id
g lasttype=l.type
mlogit type i.lasttype

A more sensible analysis might use duration with exact times of tests
and entry into into the ICU, as opposed to simple order of test for
infection, and try to isolate the actual mechanism causing the
observed clustering, perhaps using a competing risks analysis on time
to infection (with leaving the ICU being a censoring event). A good
model should incorporate a deep understanding of the science and
setting, which I do not have for fungal infections in an ICU.  I would
suspect ceiling tiles before staff, for example, but you clearly have
a reason for suspecting the staff of transmitting the infections.

On Wed, Dec 21, 2011 at 5:50 PM, roland andersson
<rolandersson@gmail.com> wrote:
> Austin
<snip>
> I do not understand what you mean by  "You could just run an -mlogit-
> of type on last type"?

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