Re: st: Categorical variable

[Richard Williams <Richard.A.Williams.5@ND.edu>]

At 08:34 AM 7/22/2005 -0400, ALICE DOBSON wrote:
> Dear All,
> I use stata 9 and have a very simple question.
>
> I have a categorical independent variable [Level of Investment] in an 
> unbalanced panel of firms. All firms fall within the three categories: 
> Low, Medium, and High investments. I code them as 1 or 0 for each 
> category, which are exclusive. If a firm has low level of investment then 
> it canot have medium or high.
>
> My question is how do I explain to Stata that this is a categorical 
> variable and which of the three should be the base dummy?
Lots of ways.

* Use the -xi- command

* (My favorite) Create dummies and exclude the one you want as the base, e.g.

tab1 var, gen(dummy_)

* Some commands, such as -anova-, include options to specify which vars are 
categorical or continuous.


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Richard Williams, Notre Dame Dept of Sociology
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