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RE: st: crude binary analysis


From   "Matt Spittal" <Matt.Spittal@cancervic.org.au>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: crude binary analysis
Date   Mon, 25 Aug 2008 10:03:28 +1000

Sahid,

See -help xi- for information on controlling the reference category (specifically, the section 'Summary of controlling the omitted dummy').

-- Matt
matt.spittal@cancervic.org.au



-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu]On Behalf Of Sahid Hocine
Sent: Monday, 25 August 2008 5:13 AM
To: statalist@hsphsun2.harvard.edu
Subject: Re: st: crude binary analysis


Steven, Thanks

I meant when i use the -tabodds- for  binary crude analysis it gives
me odds ( not OR my mistake) which i used then to calculate ratios.
thus the OR=1 for the reference chosen.
When use the xi can i specify the reference   for the or analysis (
which will have OR=1)?


On Sun, Aug 24, 2008 at 7:54 PM, Steven Samuels
<sjhsamuels@earthlink.net> wrote:
> Sahid-
>
> You asked for a version of a survey program which would match the results in
> -tabodd-.  -tabodd- has no line with a "reference group" and an entry of 1.
>  Nor does it give odds ratios (OR's) as I stated in my email.  So, exactly
> what question did you mean to ask?
>
> -Steve
>
>
>
> On Aug 24, 2008, at 2:46 PM, Sahid Hocine wrote:
>
>> Thanks,
>> In addition when i do perform the following i have  a problem since
>> the or for the first line should be 1 as reference?  Sahid
>>
>> . xi,noomit:svy:logit sd107 i.v130,nocons or
>>
>> (running logit on estimation sample)
>>
>>
>>
>> Survey: Logistic regression
>>
>>
>>
>> Number of strata   =        35                  Number of obs      =
>>  5600
>>
>> Number of PSUs     =      4823                  Population size    =
>> 5638.5227
>>
>>                                                Design df          =
>>  4788
>>
>>                                                F(   2,   4787)    =
>>  510.77
>>
>>                                                Prob > F           =
>>  0.0000
>>
>>
>>
>>
>> ------------------------------------------------------------------------------
>>
>>             |             Linearized
>>
>>       sd107 | Odds Ratio   Std. Err.      t    P>|t|     [95% Conf.
>> Interval]
>>
>>
>> -------------+----------------------------------------------------------------
>>
>>    _Iv130_1 |    .016556   .0021707   -31.28   0.000     .0128034
>>  .0214084
>>
>>    _Iv130_2 |   .0087124   .0062621    -6.60   0.000      .002129
>>  .0356531
>>
>>
>> ------------------------------------------------------------------------------
>>
>> On Sun, Aug 24, 2008 at 7:43 PM, Sahid Hocine <cahid2@googlemail.com>
>> wrote:
>>>
>>> Thanks,
>>> In addition when i do perform the following i have  a problem since the
>>> or for the first line should be 1 as reference?  Sahid
>>>
>>> . xi,noomit:svy:logit sd107 i.v130,nocons or
>>>
>>> (running logit on estimation sample)
>>>
>>>
>>>
>>> Survey: Logistic regression
>>>
>>>
>>>
>>> Number of strata   =        35                  Number of obs      =
>>>  5600
>>>
>>> Number of PSUs     =      4823                  Population size    =
>>> 5638.5227
>>>
>>>                                                Design df          =
>>>  4788
>>>
>>>                                                F(   2,   4787)    =
>>>  510.77
>>>
>>>                                                Prob > F           =
>>>  0.0000
>>>
>>>
>>>
>>>
>>> ------------------------------------------------------------------------------
>>>
>>>             |             Linearized
>>>
>>>       sd107 | Odds Ratio   Std. Err.      t    P>|t|     [95% Conf.
>>> Interval]
>>>
>>>
>>> -------------+----------------------------------------------------------------
>>>
>>>    _Iv130_1 |    .016556   .0021707   -31.28   0.000     .0128034
>>>  .0214084
>>>
>>>    _Iv130_2 |   .0087124   .0062621    -6.60   0.000      .002129
>>>  .0356531
>>>
>>>
>>> ------------------------------------------------------------------------------
>>>
>>> On Sun, Aug 24, 2008 at 4:00 PM, Steven Samuels
>>> <sjhsamuels@earthlink.net> wrote:
>>>>
>>>> Sahid, -taboods- gives crude odds, not odds ratios.
>>>> Use -svy: logit-   with -xi, noomit-; drop the constant, and add option
>>>> "or".
>>>>
>>>> Note: when referring to commands on Statalist, use hyphens around their
>>>> names:  -tabodds-
>>>>
>>>> -Steve
>>>>
>>>> /**************************************************/
>>>> sysuse auto, clear
>>>> gen rep= rep78<=3
>>>> tab rep
>>>> svyset _n
>>>>
>>>> tabodds rep foreign
>>>> /* Now svy: logit */
>>>> xi, noomit : svy: logit rep i.foreign, nocons or
>>>> /*************************************************/
>>>>
>>>> On Aug 24, 2008, at 10:29 AM, Sahid Hocine wrote:
>>>>
>>>>> Dear Stalister,
>>>>>
>>>>> I have a question regarding Stata 10 being a newbee on the field.
>>>>>
>>>>> I am analyzing a DHS data set *(survey) and for  the bivariate crude
>>>>> analysis I am used to   tabodds  however it is not supported by the
>>>>> svy , so I guess  I would have to use the logistic command for binary
>>>>> analysis but the output is not what I want i.e a crude odd ratio by
>>>>> category. Can I proceed with the svy or the stratification is the only
>>>>> solution?
>>>>>
>>>>> Waiting for your help
>>>>>
>>>>> Sahid
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> . svy:logistic sd107 v130
>>>>> (running logistic on estimation sample)
>>>>>
>>>>> Survey: Logistic regression
>>>>>
>>>>> Number of strata   =        35                  Number of obs      =
>>>>>    5600
>>>>> Number of PSUs     =      4823                  Population size    =
>>>>> 5638.5227
>>>>>                                               Design df          =
>>>>>  4788
>>>>>                                               F(   1,   4788)    =
>>>>>  0.77
>>>>>                                               Prob > F           =
>>>>>  0.3795
>>>>>
>>>>>
>>>>> ------------------------------------------------------------------------------
>>>>>            |             Linearized
>>>>>      sd107 | Odds Ratio   Std. Err.      t    P>|t|     [95% Conf.
>>>>> Interval]
>>>>>
>>>>> -------------+----------------------------------------------------------------
>>>>>       v130 |   .5262408   .3844291    -0.88   0.380     .1256632
>>>>>  2.203743
>>>>>
>>>>> ------------------------------------------------------------------------------
>>>>>
>>>>> . svy:tabodds sd107 v130
>>>>> tabodds is not supported by svy with vce(linearized); see help svy
>>>>> estimation for a list of Stata estimation commands
>>>>> that are supported by svy
>>>>> r(322);
>>>>>
>>>>> . :tabodds sd107 v130
>>>>> unrecognized command:  : invalid command name
>>>>> r(199);
>>>>>
>>>>> . tabodds sd107 v130
>>>>>
>>>>>
>>>>> --------------------------------------------------------------------------
>>>>>     v130  |      cases     controls       odds      [95% Conf.
>>>>> Interval]
>>>>>
>>>>> ------------+-------------------------------------------------------------
>>>>>    muslim |         81         5218    0.01552        0.01246   0.01933
>>>>>  christian |          3          298    0.01007        0.00323
>>>>> 0.03139
>>>>>
>>>>> --------------------------------------------------------------------------
>>>>> Test of homogeneity (equal odds): chi2(1)  =     0.55
>>>>>                                 Pr>chi2  =   0.4602
>>>>>
>>>>> Score test for trend of odds:     chi2(1)  =     0.55
>>>>>                                 Pr>chi2  =   0.4602
>>>>> *
>>>>> *   For searches and help try:
>>>>> *   http://www.stata.com/help.cgi?search
>>>>> *   http://www.stata.com/support/statalist/faq
>>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>>
>>>> *
>>>> *   For searches and help try:
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>>>> *   http://www.ats.ucla.edu/stat/stata/
>>>
>> *
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>
> *
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