Re: st: wsanova syntax

[David Airey <david.airey@vanderbilt.edu>]

> Christian Genova wrote:
>
> Can someone kindly lend assistance on the wsanova syntax for repeated
> measures. I'm still a novice with STATA so hope anyone can assist.
>
> There are 2 repeated variables: id and control.  ID is person  
> belonging
> to group "control".  Tthe same persons in year 1 (id) belonging to  
> group
> (control) were analyzed in time 2.
> I want to compare the scores in time 1 and 2, between time (scores in
> time 1 compared with scores in time 2) and control in time 1 and 2
> (whether there was signicant difference in scores of "control 1" at  
> time
> 1 to scores at time 2, and within "control" in time 1 and 2 (whether
> there was significant difference between scores of "control 1 and  
> 2" in
> time 1 compared to time 2).
>
> time      id    control    score
> ----------------------------------
> 1         1      1            5
> 1         2      1            6
> 1         3      1            5
> 1         1      2            3
> 1         2      2            4
> 2         1      1            7
> 2         2      1            8
> 2         3      1            5
> 2         1      2            2
> 2         2      2            10
>
> I used:   wsanova  SCORE CONTROL, id(ID) between(TIME).  Is this  
> correct?

In the sample data, id==3 is not crossed with time and control. If  
time and control were both repeated variables, every level of time  
and control would be found in every id. Is this subset of the data,  
or is it the complete listing? You have just three subjects?

The standard Stata command (anova) handles repeated variables. No  
reason to use wsanova. See the Stata FAQs and the UCLA pages on Stata  
ANOVA and Stata xtmixed equivalents.

-Dave

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