st: use of logistic

[Ann Fitzmaurice <a.e.fitzmaurice@abdn.ac.uk>]

hi

i have data thast was collected at the individual level,  but the pupils 
are from different schools

i have tried the following with and without the cluster option

what i am trying to do is to see if there are any school effects  but not 
sure if logistic is the right method, and if so , how can i tell from the 
output if there are are school effects


. xi:logistic  E35_LR1 i.REGION, cluster( SCHOOL)
i.REGION          _IREGION_1-2        (naturally coded; _IREGION_1 omitted)

Logit estimates                                   Number of obs   =       8539
                                                  Wald chi2(1)    =       4.52
                                                  Prob > chi2     =     0.0334
Log likelihood = -4459.2514                       Pseudo R2       =     0.0039

                           (standard errors adjusted for clustering on SCHOOL)
------------------------------------------------------------------------------
             |               Robust
     E35_LR1 | Odds Ratio   Std. Err.      z    P>|z|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
  _IREGION_2 |    1.39198    .216436     2.13   0.033     1.026317    1.887924
------------------------------------------------------------------------------

. xi:logistic  E35_LR1 i.REGION,
i.REGION          _IREGION_1-2        (naturally coded; _IREGION_1 omitted)

Logit estimates                                   Number of obs   =       8539
                                                  LR chi2(1)      =      35.32
                                                  Prob > chi2     =     0.0000
Log likelihood = -4459.2514                       Pseudo R2       =     0.0039

------------------------------------------------------------------------------
     E35_LR1 | Odds Ratio   Std. Err.      z    P>|z|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
  _IREGION_2 |    1.39198   .0784069     5.87   0.000     1.246484    1.554459
------------------------------------------------------------------------------
thanks for any advice
regards
ann

------------
Ann Fitzmaurice
Medical Statistician
Dugald Baird Centre for Research on Women's Health
Aberdeen Maternity Hospital
University of Aberdeen
Aberdeen AB25 2ZL
Uk
a.e.fitzmaurice@abdn.ac.uk

Tel . 01224 553876

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