Re: st: Syntax to specify clustering on a variable or turn off clustering

[Nick Cox <njcoxstata@gmail.com>]

Have a look at

SJ-9-3  pr0048  . . . . . . . . .  Stata tip 79: Optional arguments to options
        . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  N. J. Cox
        Q3/09   SJ 9(3):504                                      (no commands)
        tip showing programmers how to provide an option that
        can be specified with or without arguments

http://www.stata-journal.com/sjpdf.html?articlenum=pr0048

Nick

On Wed, Mar 27, 2013 at 4:41 PM, Nicholas Potter
<potter.nicholas@gmail.com> wrote:

> I'm trying to write a program that will use clustering on a variable by
> default, but also give the user the option to turn it off or to cluster on
> a different variable. The problem is that including both "cluster(varname)"
> and "nocluster" in the syntax definition results in the cluster option not
> being stored.
>
> For example:
>
> program define regress2
>
> syntax varlist [if] [in] [aw fw iw/] [, cluster(passthru) nocluster ]
> ...
> if "`cluster'"=="nocluster" {
>   reg yvar xvars
> }
> else if "`cluster'"=="" {
>   reg yvar xvars, cluster(foriegn)
> }
> else {
>   reg yvar xvars, `cluster'
> }
>
> end
>
> This will default to cluster(foreign) regardless of whether a
> cluster(varname) option is passed:
>
> webuse auto, clear
> regress2 price mpg rep78 --> program clusters on foreign
> regress2 price mpg rep78, cluster(make) --> program clusters on foreign
> regress2 price mpg rep78, nocluster --> no clustering is used
>
>
> the second command should cluster on make instead of on foreign.
>
> Any thoughts or recommendations? I could change nocluster to clusteroff or
> something, but that wouldn't be in keeping with stata syntax convention.
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