help groupdata
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Title

    groupdata -- Prepares data for grouped conditional logit regression

Syntax

        groupdata varlist ,  dep(depvar) groupid(groupid) choiceid(choiceid)

where:
groupid is a unique group identifier
choiceid is a unique choice identifier

Description

    groupdata converts the data set in memory to a new data set that can be
    used with commands that deal with multinomial type data such as grouped
    conditional logit multin and dirichlet-multinomial regression dirmul.
    The dataset in memory must be in the format required by the command 
    clogit.  Suppose you have a data set in the format required by clogit:

y  x1  x2 gid cid
0   0   4   1   1
0   1   4   1   2
1   1   6   1   3
1   2   2   2   1
0   1   4   2   2
0   3   5   2   3
0   0   4   3   1
1   1   4   3   2
0   1   6   3   3
0   2   6   4   1
1   3   7   4   2
0   2   5   4   3
0   1   5   4   4
1   2   2   5   1
0   1   4   5   2
0   3   5   5   3

After issuing the command

    . groupdata x1 x2, dep(y) groupid(gid) choiceid(cid)

your data will look like

x1  x2  gid cid y
0   4   1   1   0
1   4   1   2   1
1   6   1   3   1
2   2   2   1   2
1   4   2   2   0
3   5   2   3   0
2   6   4   1   0
3   7   4   2   1
2   5   4   3   0
1   5   4   4   0

Examples

    . groupdata age gender, dep(y) gr(id) ch(choice)

Author

Paulo Guimaraes, Division of Research, University of South Carolina.
Email: guimaraes@moore.sc.edu 

Also See