problem dummy variables, no dummy trap

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sabineH
Posts: 3
Joined: Sun May 11, 2014 6:05 am

problem dummy variables, no dummy trap

Postby sabineH » Mon May 12, 2014 6:13 am

Hello,
I have a problem with my dummy variables, I read the guide about dummies, the eviews manual and did some research on the internet and on this website, but unfortunately my dummy variables in my panel dataset are still not working. this is my model:

cfp_roa_wins c csp_cg_average(-1) csp_env_average(-1) csp_soc_average(-1) crisis_dummy crisis_dummy*csp_cg_average(-1) crisis_dummy*csp_env_average(-1) crisis_dummy*csp_soc_average(-1) risk_wins @log(ws_totalassets) @expand(year,@droplast) @expand(country, @drop("AUS")) @expand(industry_code,@dropfirst)

With the @drop command I thought I circumvented the dummy trap. I build up the model one variable at the time, but all three dummy variables in the end are not working, when I add one or all three of them eviews states: nearly singular matrix, but since I already excluded one dummy with the @drop command I do not know what to do to change the dummies so the equation can be run.

Can you maybe help me what I can do to make my model work?
I would very much appreciate your help!
I am working in Eviews 7, version 7.2 serial nr: 70K00168

ps. for some reason I am not able to attach my workfile, I tried it in internet explorer and mozilla firefox.

startz
Non-normality and collinearity are NOT problems!
Posts: 3796
Joined: Wed Sep 17, 2008 2:25 pm

Re: problem dummy variables, no dummy trap

Postby startz » Mon May 12, 2014 7:04 am

Check your nondummy variables: Are any of them constant with respect to industry, country, or year?

sabineH
Posts: 3
Joined: Sun May 11, 2014 6:05 am

Re: problem dummy variables, no dummy trap

Postby sabineH » Tue May 20, 2014 6:14 am

Dear Startz,
thanks for your response, I've checked and none of my nondummy variables are constant with resprect to industry, country or year.
I am still not able to run a regression on my full model, do you maybe know other factors that can cause my problem?
Best regards, Sabine

samijo
Posts: 36
Joined: Thu Sep 18, 2008 12:15 pm
Location: CO. USA

Re: problem dummy variables, no dummy trap

Postby samijo » Tue May 20, 2014 6:34 am

check for the correlation between the variables, two of them might be identical or highly correlated to induce a near singular matrix error!


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