UNSTRUCTURED WORKING CORRELATION 
 

 GEE:  GENERALIZED LINEAR MODELS FOR DEPENDENT DATA
 gee S-function, version 4.13 modified 98/01/27 (1998) 

Model:
 Link:                      Logarithm 
 Variance to Mean Relation: Poisson 
 Correlation Structure:     Unstructured 

Call:
gee(formula = seize ~ logbase + logage + trt + visit4 + basetrt, 
    id = subj, family = poisson, corstr = "unstructured")

Summary of Residuals:
        Min          1Q      Median          3Q         Max 
-14.1473158  -2.9156034  -0.5648066   1.6966299  59.7187817 


Coefficients:
              Estimate Naive S.E.   Naive z Robust S.E.  Robust z
(Intercept) -3.0703916 1.21744843 -2.521989  0.94492946 -3.249334
logbase      0.9370925 0.12911640  7.257734  0.09289341 10.087825
logage       1.0008969 0.34772442  2.878420  0.27372135  3.656627
trt         -1.4973787 0.46765660 -3.201877  0.42230224 -3.545751
visit4      -0.1559873 0.09499776 -1.642010  0.07831289 -1.991847
basetrt      0.6280492 0.18899638  3.323076  0.16985140  3.697639

Estimated Scale Parameter:  4.45469
Number of Iterations:  4

Working Correlation
          [,1]      [,2]      [,3]      [,4]
[1,] 1.0000000 0.2846098 0.2608401 0.1563989
[2,] 0.2846098 1.0000000 0.6519718 0.3479656
[3,] 0.2608401 0.6519718 1.0000000 0.4617796
[4,] 0.1563989 0.3479656 0.4617796 1.0000000

 
EXCHANGEABLE WORKING CORRELATION 
 

 GEE:  GENERALIZED LINEAR MODELS FOR DEPENDENT DATA
 gee S-function, version 4.13 modified 98/01/27 (1998) 

Model:
 Link:                      Logarithm 
 Variance to Mean Relation: Poisson 
 Correlation Structure:     Exchangeable 

Call:
gee(formula = seize ~ logbase + logage + trt + visit4 + basetrt, 
    id = subj, family = poisson, corstr = "exchangeable")

Summary of Residuals:
        Min          1Q      Median          3Q         Max 
-14.2804674  -2.9024753  -0.4940558   1.7757319  59.8699344 


Coefficients:
              Estimate Naive S.E.   Naive z Robust S.E.  Robust z
(Intercept) -2.7933674 1.22877062 -2.273303  0.95596337 -2.922044
logbase      0.9504074 0.13152324  7.226156  0.09869915  9.629338
logage       0.9064447 0.35118728  2.581086  0.27715935  3.270482
trt         -1.3386276 0.47277353 -2.831435  0.42951137 -3.116629
visit4      -0.1610871 0.09219968 -1.747155  0.06558188 -2.456275
basetrt      0.5632558 0.19152488  2.940902  0.17485489  3.221276

Estimated Scale Parameter:  4.414352
Number of Iterations:  2

Working Correlation
          [,1]      [,2]      [,3]      [,4]
[1,] 1.0000000 0.3551212 0.3551212 0.3551212
[2,] 0.3551212 1.0000000 0.3551212 0.3551212
[3,] 0.3551212 0.3551212 1.0000000 0.3551212
[4,] 0.3551212 0.3551212 0.3551212 1.0000000

 
AR(1) WORKING CORRELATION 
 

 GEE:  GENERALIZED LINEAR MODELS FOR DEPENDENT DATA
 gee S-function, version 4.13 modified 98/01/27 (1998) 

Model:
 Link:                      Logarithm 
 Variance to Mean Relation: Poisson 
 Correlation Structure:     AR-M , M = 1 

Call:
gee(formula = seize ~ logbase + logage + trt + visit4 + basetrt, 
    id = subj, b = c(-2, 1, 1, -1, -0.1, 0.5), family = poisson, 
    corstr = "AR-M", Mv = 1)

Summary of Residuals:
        Min          1Q      Median          3Q         Max 
-14.1147621  -2.9201518  -0.5479669   1.6786673  59.6736888 


Coefficients:
              Estimate Naive S.E.   Naive z Robust S.E.  Robust z
(Intercept) -3.0525967 1.19717709 -2.549829  0.93848186 -3.252697
logbase      0.9444762 0.12699946  7.436852  0.09276876 10.180973
logage       0.9907881 0.34191424  2.897768  0.27370217  3.619950
trt         -1.4828350 0.46042681 -3.220566  0.41682111 -3.557485
visit4      -0.1551820 0.09626332 -1.612057  0.08922172 -1.739285
basetrt      0.6192620 0.18592401  3.330727  0.16921026  3.659719

Estimated Scale Parameter:  4.462371
Number of Iterations:  5

Working Correlation
          [,1]      [,2]      [,3]      [,4]
[1,] 1.0000000 0.4661711 0.2173155 0.1013062
[2,] 0.4661711 1.0000000 0.4661711 0.2173155
[3,] 0.2173155 0.4661711 1.0000000 0.4661711
[4,] 0.1013062 0.2173155 0.4661711 1.0000000