[R] ergm

[Iasonas Lamprianou]

Dear colleagues,

I have another question, which, I think cannot be answered easily by the manual. What is the effect of including both nodefactor("Gender") and nodematch("Gender",diff=TRUE)) for the same variable in the model? Judging from the output (please see below), you cant have estimates for both for boys and girls forthe nodematch command, but I thought that the nodematch measures for boys and girls were not related. Does the nodematch command show the relative frequency of matching boy-boy against girl-girl, so one of the two categories has to be a reference category? Thank you

Formula:   ng ~ edges + nodefactor("Gender") + nodematch("LEA", diff = TRUE) + 
    nodematch("Gender", diff = TRUE)

Newton-Raphson iterations:  5 

Maximum Likelihood Results:
                        Estimate Std. Error MCMC s.e. p-value    
edges                  -2.098842   0.033393        NA  <1e-04 ***
nodefactor.Gender.Girl  0.612314   0.021956        NA  <1e-04 ***
nodematch.LEA.1         0.018116   0.032228        NA  0.5740    
nodematch.LEA.3        -0.002688   0.154005        NA  0.9861    
nodematch.LEA.4         0.103054   0.043836        NA  0.0187 *  
nodematch.LEA.5         0.016844   0.033565        NA  0.6158    
nodematch.LEA.6        -0.086837   0.100466        NA  0.3874    
nodematch.Gender.Boy    0.593721   0.038632        NA  <1e-04 ***
nodematch.Gender.Girl         NA   0.000000        NA      NA    
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1 

For this model, the pseudolikelihood is the same as the likelihood.

    Null  Deviance: 92092  on 66430  degrees of freedom
 Residual Deviance: 67948  on 66421  degrees of freedom
          Deviance: 24144  on     9  degrees of freedom
 
AIC: 67966    BIC: 68048 




Dr. Iasonas Lamprianou


Assistant Professor (Educational Research and Evaluation)
Department of Education Sciences
European University-Cyprus
P.O. Box 22006
1516 Nicosia
Cyprus 
Tel.: +357-22-713178
Fax: +357-22-590539


Honorary Research Fellow
Department of Education
The University of Manchester
Oxford Road, Manchester M13 9PL, UK
Tel. 0044  161 275 3485
iasonas.lamprianou at manchester.ac.uk