gistfile1.txt

. do "/var/folders/47/f2b3zfds1y5gq4vp7m6___cr0000gn/T//SD44048.000000"

. clear all

. set seed 123

. 
. * recruit subjects (if only this easy...)
. set obs 2000
number of observations (_N) was 0, now 2,000

. 
. * assign to groups
. gen mbct =  mod(_n, 2)

. 
. * depression baseline score
. gen d0 = rnormal(0,1)

. 
. * generate probability of relapse note - no interaction term here
. gen p =  max(min(.5*d0 + .3*mbct, .99), 0.01)

. 
. 
. gen y = rbinomial(1,p)

. summ y

    Variable |        Obs        Mean    Std. Dev.       Min        Max
-------------+---------------------------------------------------------
           y |      2,000       .2875    .4527099          0          1

. 
. * ns interaction term in the logistic regression
. logistic y mbct##c.d0

Logistic regression                             Number of obs     =      2,000
                                                LR chi2(3)        =    1054.64
                                                Prob > chi2       =     0.0000
Log likelihood = -672.47361                     Pseudo R2         =     0.4395

------------------------------------------------------------------------------
           y | Odds Ratio   Std. Err.      z    P>|z|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
      1.mbct |   3.006289   .5619068     5.89   0.000     2.084166    4.336399
          d0 |   11.49553   2.036777    13.78   0.000     8.122942     16.2684
             |
   mbct#c.d0 |
          1  |   1.545352   .3948197     1.70   0.088     .9366024    2.549762
             |
       _cons |   .0959822   .0144456   -15.57   0.000     .0714632    .1289137
------------------------------------------------------------------------------

. 
. * but get ES estimates in probability domainfo 1 SD above and below mean baseline 
. margins, dydx(mbct) at(d0=(-1(1)1)) 

Conditional marginal effects                    Number of obs     =      2,000
Model VCE    : OIM

Expression   : Pr(y), predict()
dy/dx w.r.t. : 1.mbct

1._at        : d0              =          -1

2._at        : d0              =           0

3._at        : d0              =           1

------------------------------------------------------------------------------
             |            Delta-method
             |      dy/dx   Std. Err.      z    P>|z|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
1.mbct       |
         _at |
          1  |    .007703   .0048014     1.60   0.109    -.0017077    .0171136
          2  |   .1363576   .0227078     6.00   0.000     .0918512    .1808641
          3  |   .3121895   .0367425     8.50   0.000     .2401756    .3842033
------------------------------------------------------------------------------
Note: dy/dx for factor levels is the discrete change from the base level.

. 
. 
end of do-file