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Re: st: no results for random effects in -cmp-


From   Karen Ruckman <[email protected]>
To   [email protected]
Subject   Re: st: no results for random effects in -cmp-
Date   Fri, 1 Nov 2013 12:08:59 -0700 (PDT)

thanks for your response, stephen. actually, i wasn't referring to the estimate of "/lnsig_1_1" but rather to the estimate underneath the section titled "random effects parameters". the estimate for "level:number" is 2.0e-163 which is basically zero. if your logic applies to this estimate, then we can assume that because the random effects are estimated to be so close to zero, a SE is impossible to estimate. can anyone confirm for me whether this means that the observations do not significantly differ between groups (where groups are determined by the random effects variable which in this case is "number"). i am really hoping to get an interpretation for why there is no SE for the random effects parameter estimate. 



----- Original Message -----
From: "S Jenkins" <[email protected]>
To: [email protected]
Sent: Friday, November 1, 2013 2:52:37 AM
Subject: st: no results for random effects in -cmp-

Karen Ruckman <[email protected]> asks why no SE is estimated when she fits a model using -cmp- and refers us to the estimates associated with "/lnsig_1_1". Her point estimate for this is  -374.6105. Note that -cmp- is estimating the log of a variance here, so the estimated variance is exp(-374) which is effectively zero ... and hence almost impossible to also derive an associated SE.  This suggests to me that Karen should fit a simpler version of her model in which the variance is constrained to be zero. (I don't know enough about her model to know whether the constraint on /lnsig_3 is relevant to this.)

Stephen

-----------------------
Date: Thu, 31 Oct 2013 10:46:10 -0700 (PDT)
From: Karen Ruckman <[email protected]>
Subject: st: no results for random effects in -cmp-

i am using the user written command -cmp- which, i believe is similar to -xtmixed-. i have included random effects in the final stage of an endogenous system, however the results show no standard error for the random effects parameter. i cannot make out what this means. i have tried to alter the number of integration points and integration method to no avail. does anyone know what this means? is there another way to attain an estimate for the random effects? 

thanks for your time,
karen.


for your information, i have included the stata results below:


. cmp  ($dept_var = $controls_ff $context $dirvar $grpvar || number: ) ($dirvar = $controls_1 ) ($grpvar = $controls_gp ) if $include & dimension==1,  indicators(4 4 1) constraint(1 2) qui

Fitting individual models as starting point for full model fit.

Fitting full model.

Mixed-process multilevel regression               Number of obs   =        577
                                                  Wald chi2(23)   =    2229.72
Log likelihood =  -1156.539                       Prob > chi2     =     0.0000

 ( 1)  [lnsig_3]_cons = 0
- -----------------------------------------------------------------------------------
                  |      Coef.   Std. Err.      z    P>|z|     [95% Conf. Interval]
- ------------------+----------------------------------------------------------------
dept_var_wdlST_ET |
      lrevenue_ff |  -.0030602   .0039996    -0.77   0.444    -.0108992    .0047788
           age_ff |    .002449     .00128     1.91   0.056    -.0000597    .0049578
       private_ff |  -.0200168   .0600785    -0.33   0.739    -.1377685    .0977348
       foreign_ff |  -.0509546   .0310616    -1.64   0.101    -.1118342     .009925
   firm_in_mkt_ff |  -.0067307    .008386    -0.80   0.422    -.0231669    .0097055
         year_dum |  -.0436844   .0174679    -2.50   0.012    -.0779209   -.0094479
     largest_wdl |  -.0436173   .0421438    -1.03   0.301    -.1262176     .038983
     high_pop_wdl |   .0709239   .0428823     1.65   0.098    -.0131239    .1549718
       dr_wdlST_1 |    .009178   .0183724     0.50   0.617    -.0268312    .0451873
       rg_wdlST_5 |   .9929262   .0305494    32.50   0.000     .9330505    1.052802
            _cons |  -.2982327    .049376    -6.04   0.000     -.395008   -.2014575
- ------------------+----------------------------------------------------------------
dr_wdlST_1        |
      DR_inst_wdl |   .1433616   .0688173     2.08   0.037     .0084822    .2782411
            _cons |   -.463913   .0593736    -7.81   0.000    -.5802832   -.3475428
- ------------------+----------------------------------------------------------------
rg_wdlST_5        |
      GR_inst_wdl |   .1747824     .01903     9.18   0.000     .1374843    .2120805
            _cons |   .2591684   .0118572    21.86   0.000     .2359287     .282408
- ------------------+----------------------------------------------------------------
       /lnsig_1_1 |  -374.6105          .        .       .            .           .
         /lnsig_3 |          0  (constrained)
     /atanhrho_12 |  -1.269019   .1020839   -12.43   0.000      -1.4691   -1.068938
     /atanhrho_13 |  -2.757483   .0906748   -30.41   0.000    -2.935203   -2.579764
     /atanhrho_23 |   1.277725   .1049671    12.17   0.000     1.071994    1.483457
- -----------------------------------------------------------------------------------
- ------------------------------------------------------------------------------------
Random-effects Parameters           |  Estimate    Std. Err.    [95% Conf. Interval]
- ------------------------------------+-----------------------------------------------
Level: number                       |
  dept_var_wdlS~T                   |
    Standard deviations             | 
      _cons                         |  2.0e-163          .
- ------------------------------------+-----------------------------------------------
Level: Residuals                    |
 Standard deviations                | 
  dept_var_wdlST_ET                 |         1  (constrained)
  dr_wdlST_1                        |         1  (constrained)
  rg_wdlST_5                        |         1          .
 Cross-eq correlations              | 
  dept_var_wdlS~T dr_wdlST_1        | -.8535315    .0277141    -.8994055   -.7890608
  dept_var_wdlS~T rg_wdlST_5        | -.9919802    .0014486    -.9943724   -.9885768
  dr_wdlST_1      rg_wdlST_5        |  .8558777    .0280759     .7902112    .9021137
- ------------------------------------------------------------------------------------


Stephen
------------------
Stephen P. Jenkins <[email protected]>

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