[R-sig-ME] zero-truncated mixed effects logistic regression?
David Duffy
David.Duffy at qimr.edu.au
Wed Jan 18 00:27:56 CET 2012
On Tue, 17 Jan 2012, Martin Schmettow wrote:
> The problem I have is similar to the capture-recapture approach for
> estimating abundance. In my case the captured animals are design flaws of
> software.
>
> A given number of testers independently tries to find these flaws, which
> makes it a binomial problem. However, flaws that were never discovered
> during the study are not known to the experimenter.
> Furthermore this is a crossed mixed-effects
> situation as
> discovery trials are repeated over testers and flaws.
>
> (1) Does effectiveness of testers increases with years of experience?
> (2) Are certain classes of flaws easier to find than others?
>
> A general finding of previous research is that testers as well as flaws are
> heterogeneous. Some flaws are less visible than others and testers differ in
> overall effectiveness. Hence, random effects are needed to account for
> overdispersion, right?
I may be corrected, but I think your setup is "actually" a Rasch type
model with each flaw being an item. Some flaws are just too difficult to
see, ie the item is "too hard". I presume, given your research questions,
you are not actually interested in estimating the number of undetected
flaws from each class, so a missing data type setup is not really needed.
http://www.jstatsoft.org/v20/a02/paper
is one paper from our esteemed leader ;)
--
| 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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