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help parmby_only_opts                                            (Roger Newson)
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Options for parmby only


Syntax


    options                   Description
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    by(varlist)               Specify variables defining by-groups
    command                   Add a variable containing the command called
    -------------------------------------------------------------------------


Description

    These options may not be specified for parmest.  They allow the user to
    call an estimation command once for each of a set of by-groups, and to
    create an the output dataset (or resultsset) with one observation per
    parameter per by-group.


Options

    by(varlist) specifies a list of existing variables which would normally
        appear in the by varlist: section of the Stata estimation command
        called by parmby.  parmby creates an output dataset with one
        observation for each parameter in each by-group in which the command
        executed successfully.  The output dataset contains values of the
        by-variables in each by-group (if by() is specified), in addition to
        the variables created by parmest.  However, the by() option is
        optional, and parmby will still work without it, creating an output
        dataset with one observation per parameter of a single set of
        estimation results.

    command is a variable-adding option.  If specified, it creates a string
        variable named command in the output dataset, containing the text of
        the estimation command called by parmby.  The text of the command is
        truncated, if necessary, to the maximum length of a string variable
        under the edition of Stata currently in use, which is 244 characters
        in Stata Version 9. (See help for limits.) The variable command has
        the same value in all observations in the output dataset, and is
        useful as an identifier if the user creates multiple parmby output
        datasets, using different commands, and concatenates them using 
        append, or using dsconcat if installed.


Notes

    Note that the variable command can be renamed by the rename() option, but
    the variables specified in by(varlist) cannot.  See help for
    parmest_varmod_opts for details on the rename() option, and help for
    parmest_resultssets for details of other variables in the output datasets
    (or resultssets} produced by parmest and parmby.


Author

    Roger Newson, Imperial College London, UK.  Email:
    r.newson@imperial.ac.uk


Also see

     Manual: [D] append, [D] by, [U] 11.4 varlists, [U] 20 Estimation and
             postestimation commands
    On-line: help for append, by, varlist, estimation commands
             help for parmest, parmby, parmest_outdest_opts, parmest_ci_opts,
             parmest_varadd_opts, parmest_varmod_opts, parmest_resultssets
             help for dsconcat if installed