Ordered categorical responses; The SOCATT data

ADMB Files
Code: socatt.tpl
Data: socatt.dat
Initial values: socatt.pin
All required files (DOS): socatt.zip
All required files (linux): socatt.tar.gz
Results: socatt.par

Running ADMB-executables
In a DOS window
Under linux

Results: Computation times
ADMB-RE 30 seconds
aML 10-15 seconds
SAS 50-60seconds
MLwiN 10-15 seconds
HLM 5 50-60 seconds
MIXOR 5-10 seconds

Computation times for other packages taken from here.

ADMB-RE home
Otter Research

Model description

The SOCATT data set is used in the comparison of different software packages for multilevel modelling, conducted by the Centre for Multilevel Modelling. The SOCATT data consist of the responses to a set of dichotomous items on a woman's right to have an abortion. The outcome variable (yij) is a score constructed from these items ranging from 1 to 7, with a higher score corresponding to stronger support for abortion. Each of 264 respondents was asked the same set of questions on four occasions, 1983-1986, and yij denotes the response from individual i in year j. We consider one categorical covariate (religion) with 4 categories. A random intercept ordered logit model was fitted:

logit[ P(yij < s) ] = ks + b1xi1 + b2*xi2 + b3*xi3 + ui,
ui ~ N(0,s2)
where x1i, x2i and x3i are dummy variables coding for the different levels of the categorical covariates, and ks are threshold parameters. A full description of the model can be found here: socatt.pdf


The following table shows the parameter estimates obtained with ADMB-RE.

t1 t2 t3 t4 t5 t6 s b1 b2 b3
-4.13 -2.39 0.4 1.34 2.23 3.27 2.23 1.95 0.68 2.78

Results for other software packages can be obtained here.