Hello. i'm running a maultivariable panel regression model with xtgee and a number of continuous and categorical indepentent variables. I'm trying to get contrasts of marginal effects of an indicator variable, and can set different base levels using ibX.variable notation.. I can run marginal elasticities with eydx.
Code:
 . margins i.hour6

Adjusted predictions                            Number of obs     =      7,801
Model VCE    : Semirobust

Expression   : Exponentiated linear prediction, predict()

------------------------------------------------------------------------------
             |            Delta-method
             |     Margin   Std. Err.      z    P>|z|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
       hour6 |
          0  |    154.271   4.230974    36.46   0.000     145.9785    162.5636
          1  |    147.976   3.380656    43.77   0.000       141.35    154.6019
          2  |   151.9056   3.582315    42.40   0.000     144.8844    158.9268
          3  |   157.2417   3.570002    44.05   0.000     150.2447    164.2388
          4  |   158.6969   3.750886    42.31   0.000     151.3453    166.0485
          5  |   162.7874   4.190865    38.84   0.000     154.5735    171.0014
          6  |   165.2312   5.213272    31.69   0.000     155.0134     175.449
          7  |    168.424   5.232227    32.19   0.000     158.1691     178.679
------------------------------------------------------------------------------

. margins rb5.hour6

Contrasts of adjusted predictions
Model VCE    : Semirobust

Expression   : Exponentiated linear prediction, predict()

------------------------------------------------
             |         df        chi2     P>chi2
-------------+----------------------------------
       hour6 |
   (0 vs 5)  |          1        3.17     0.0748
   (1 vs 5)  |          1       14.53     0.0001
   (2 vs 5)  |          1        8.28     0.0040
   (3 vs 5)  |          1        2.59     0.1075
   (4 vs 5)  |          1        2.63     0.1050
   (6 vs 5)  |          1        0.54     0.4643
   (7 vs 5)  |          1        2.57     0.1089
      Joint  |          7       22.90     0.0018
------------------------------------------------

--------------------------------------------------------------
             |            Delta-method
             |   Contrast   Std. Err.     [95% Conf. Interval]
-------------+------------------------------------------------
       hour6 |
   (0 vs 5)  |  -8.516408   4.780009     -17.88505    .8522373
   (1 vs 5)  |  -14.81144   3.886262     -22.42838   -7.194507
   (2 vs 5)  |  -10.88182   3.782032     -18.29446   -3.469169
   (3 vs 5)  |  -5.545677   3.445541     -12.29881     1.20746
   (4 vs 5)  |  -4.090535    2.52343     -9.036367    .8552972
   (6 vs 5)  |   2.443756    3.33936     -4.101269    8.988782
   (7 vs 5)  |   5.636613   3.516349     -1.255304    12.52853
--------------------------------------------------------------
, but I cant seem to change the base level:
Code:
. margins,eydx(i.hour6)

Conditional marginal effects                    Number of obs     =      7,801
Model VCE    : Semirobust

Expression   : Exponentiated linear prediction, predict()
ey/dx w.r.t. : 1.hour6 2.hour6 3.hour6 4.hour6 5.hour6 6.hour6 7.hour6

------------------------------------------------------------------------------
             |            Delta-method
             |      ey/dx   Std. Err.      z    P>|z|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
       hour6 |
          1  |  -.0416609    .018553    -2.25   0.025    -.0780241   -.0052978
          2  |  -.0154516   .0235164    -0.66   0.511    -.0615429    .0306398
          3  |   .0190735    .025897     0.74   0.461    -.0316836    .0698306
          4  |   .0282851   .0274845     1.03   0.303    -.0255835    .0821538
          5  |   .0537343   .0302089     1.78   0.075     -.005474    .1129426
          6  |   .0686347   .0351523     1.95   0.051    -.0002626    .1375319
          7  |   .0877739   .0371598     2.36   0.018      .014942    .1606058
------------------------------------------------------------------------------
Note: ey/dx for factor levels is the discrete change from the base level.

. margins,eydx(ib5.hour6)

Conditional marginal effects                    Number of obs     =      7,801
Model VCE    : Semirobust

Expression   : Exponentiated linear prediction, predict()
ey/dx w.r.t. : 1.hour6 2.hour6 3.hour6 4.hour6 5.hour6 6.hour6 7.hour6

------------------------------------------------------------------------------
             |            Delta-method
             |      ey/dx   Std. Err.      z    P>|z|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
       hour6 |
          1  |  -.0416609    .018553    -2.25   0.025    -.0780241   -.0052978
          2  |  -.0154516   .0235164    -0.66   0.511    -.0615429    .0306398
          3  |   .0190735    .025897     0.74   0.461    -.0316836    .0698306
          4  |   .0282851   .0274845     1.03   0.303    -.0255835    .0821538
          5  |   .0537343   .0302089     1.78   0.075     -.005474    .1129426
          6  |   .0686347   .0351523     1.95   0.051    -.0002626    .1375319
          7  |   .0877739   .0371598     2.36   0.018      .014942    .1606058
------------------------------------------------------------------------------
Note: ey/dx for factor levels is the discrete change from the base level.
note base level is still 0.hour6.

I could not find the coding syntax in pdf help for margins or contrast - but I'm sure I'm missing somethig obvious.
thank you