Bookmark and Share

Notice: On March 31, it was announced that Statalist is moving from an email list to a forum. The old list will shut down at the end of May, and its replacement, statalist.org is already up and running.


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: st: Binary Variables


From   Steve Samuels <sjsamuels@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Binary Variables
Date   Wed, 2 Jun 2010 10:26:35 -0400

In addition to Neil's suggestions:

• show us the commands that created the regional indicators.

Do the omitted regions change, or is it just the four that you mentioned?

If the same four:

• tab -region- against the indicators for just those four regions.
• -sum-- your predictors & outcome for those four regions.
• run the regression with just the four "problem" regions
• try the -nocons- option on the regression restricted to the four

Steve

-- 
Steven Samuels
sjsamuels@gmail.com
18 Cantine's Island
Saugerties NY 12477
USA
Voice: 845-246-0774
Fax:    206-202-4783



On Wed, Jun 2, 2010 at 10:14 AM, Neil Shephard <nshephard@gmail.com> wrote:
> On Wed, Jun 2, 2010 at 2:03 PM, Natalie Trapp <natalie.trapp@zmaw.de> wrote:
>> Hi Neil,
>>
>> I use Stata 11 and do a normal OLS estimation (with the "reg" command):
>>
>> y = dependent variable (agricultural inputs)
>> x = independent variables (climate variables, crops, etc.) and dummy
>> variables that represent the 150 regions within the EU
>>
>
> This is _not_ showing what you are typing, if you are using -regress-
> then I would expect you to have included something along the lines
> of....
>
> regress agricultural_inputs temperature crops i.region
>
>> The coefficients of the dependent variable within each region are very
>> divers and significant for about 120 regions.
>>
>>
>> My Problem is for instance, when "Schleswig Holstein" is my reference
>> group, Stata adittionally omits Valle d'Aoste, Vlaanderen and Ile de France.
>
> Could it be that there is missing data within your data structure such
> that most observations for these regions are omitted and the few that
> remain all have the same value of "agricultural_inputs".
>
>
>> Still, I don't quite understand why Stata does it, because the regions
>> (Germany, France, Netherlands) do not seem to be similar to me.
>
> "Seems" is a vague term and is based on your subjective interpretation
> of what you are expecting, and it need not be because you have the
> data, you can look at it.  Check the patterns of missing data that
> exist and how these pan out within the regions, in particular those
> that are being omitted.
>
> Stata will be omitting them for a reason (and it will often indicate
> why a particular category has been dropped).
>
> So again, pasting the _exact_ command you are entering and the
> resulting output would be very informative to other list members.  You
> can copy and paste from the Results window directly into an email.
>
> Neil
> --
> "... no scientific worker has a fixed level of significance at which
> from year to year, and in all circumstances, he rejects hypotheses; he
> rather gives his mind to each particular case in the light of his
> evidence and his ideas." - Sir Ronald A. Fisher (1956)
>
> Email - nshephard@gmail.com
> Website - http://slack.ser.man.ac.uk/
> Photos - http://www.flickr.com/photos/slackline/
> *
> *   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:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/


© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   Site index