Extended cross-tabulations                                    (STB-10: sg12)   
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  ^xtab^ varlist1 [weight] [^if^ exp] [^in^ range]^,^ ^by(^varlist2^)^ tabulate_options

Description
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^xtab^ cross-tabulates each of the variables in varlist1 against each of the
variables in varlist2, applying the tabulate_options to each cross-tabulation.

Example
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Suppose you have 6 variables, var1, var2,... var6.  You wish to see how the
first three (var1-var3) are each related to each of the last three (var4-
var6).  Using ^xtab^, you type:

             ^xtab^ var1 var2 var3^, by(^var4 var5 var6^)^ options

This generates the following cross-tabulations:

                  var1 by var4    var1 by var5    var1 by var6
                  var2 by var4    var2 by var5    var2 by var6
                  var3 by var4    var3 by var5    var3 by var6

In each case, the options you specified would also be presented with
the cross-tabulation.

Consider this command to be a multi-way extension of the ^tab2^ command,
designed for different purposes.  For example, if you had five variables
in varlist1, and two variables in varlist2, this command would generate
ten tables.  ^tab2^ with all seven variables would generate 21 tables.

In general, if you have n1 variables in the first varlist, and n2 variables
in the second varlist, ^xtab^ will generate n1*n2 tables.  ^tab2^ applied to
the combination of each varlist will generate (n1+n2)*(n1+n2-1)/2 tables,
which will always be larger for n1>1 or n2>1.

Thus, use ^tab2^ if you really wish to see ^all^ of the two-way cross-
tabulations among a set of variables.  Use ^xtab^ if you wish to see a
specific set of variables individually cross-tabulated with another
specific set of variables.


Also see
--------
Manual: [5s] tabulate
On-line: ^help^ for ^tab^, ^etab^

Author
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Dean H. Judson, 1030 James St., Newberg, OR 97132, 503-537-0660