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# Re: st: Contract/Collapse Combination

 From Nick Cox To statalist@hsphsun2.harvard.edu Subject Re: st: Contract/Collapse Combination Date Mon, 21 May 2012 23:51:13 +0100

```This sounds to me like

contract x* entercol

Nick

On Mon, May 21, 2012 at 9:45 PM, Lucas <lucaselastic@gmail.com> wrote:
> So, I am attempting to construct a file containing a list-format 15
> (or so) -way crosstab, with frequencies of cases for each combination
> of values.  I have millions of cases, so this crosstab is appropriate.
>
> What would be ideal would be the ability to use the contract command
> but, instead of only indicating the need for one count,  could ask for
> the sum of two variables.  Assume I have a dichotomous variable (say,
> "enter college).  Those who enter college are coded 1, those who do
> not are coded zero.  I could then construct a new variable, named
> "DidNotEnter", coded 1 for those who do NOT enter college, and zero
> for those who do.
>
> If I could then write something like:
>
> collapse x1 x2 x3 x4 ... xj, freq(EnterCol) freq(DidNotEnter)  zero
>
> I could get the totals needed.  The plan is to speed processing of a
> computationally difficult model by substituting a model of counts for a
> model of individual cases.  To do this I need the total count of each
> combination and the count meeting the condition (e.g., entering college).
> My code above would, if possible, produce a file that allowed me to
> add the two frequencies to get the total.
>
> As far as I can tell, this is not possible.  What seems to be required
> is to run it with only the "Enter College" freq, then somehow break
> the two cases (EnterCollege=1 vs. EnterCollege=0) (or, alternatively,
> to keep EC==1 and run it, and then re-run with EC==0) and somehow
> combine them, an operation that seems to be begging for error in
> matching.

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```