FYI - MEM for binary response with one obs/individual
From: Lewis B Sheiner <lewis@c255.ucsf.edu>
Subject: FYI - MEM for binary response with one obs/individual
Date: Sat, 15 Sep 2001 10:22:40 -0700
So, perhaps it can be done after all, but Stuart is not sanguine ...\
Quoted reply history
-------- Original Message --------
Date: Sat, 15 Sep 2001 04:21:02 -0700 (PDT)
From: stuart@c255b.ucsf.edu
To: dennis.fisher@durect.com, lewis@c255b.ucsf.edu
>I'm basing my "can't be done" on the idea that the omega is unidentifable:
>if you have 1 success, and 1 failure, how can you
>know if the success will be a success the next time with p>.5
>(=> omega > 0) or with p=.5 (=> omega = 0)?
>
> Lewis
The highly nonlinear nature of the logistic-type model often allows
the inter-
and intra-individual variability to be separated. In one example I
just
ran, I got legitimate estimates 90% of the time. However, as we have
learned since the time of the Bailey-Gregg article in 1997, and as
we
report in our JPP article in last month's issue: When the amount of
data
per individual is very small, the estimates are not
as good as those obtained when interindividual variability is omitted
from the model. In the example I just ran, the estimates are indeed
quite poor, so poor in fact as to suggest that it would be ill-advised
to include interindividual-variability in the model.
Stu