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help for panelthin
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Identify observations for possible thinned panel dataset

        panelthin [if exp] [in range] , generate(newvar) minimum(#)


Description

    panelthin identifies observations that would belong in a thinned panel
    dataset in which observations in each panel are at least a minimum time
    apart.  The result is a new variable tagging observations in the thinned
    dataset by 1 and others by 0.


Remarks 

    panelthin assumes tsset data and automatically works separately on each
    panel in a panel dataset.

    In essence, the first observation in each panel is selected, then the
    next after at least a minimum time, and so on.

    If a thinned dataset is acceptable, then (provided that the main dataset
    is saved elsewhere) keep the set with observations tagged 1 in the new
    variable.


Options 

    generate() specifies the name of a new variable to include tags for
    selected observations. It is a required option.

    minimum() specifies the minimum acceptable spacing in the units of the
    time variable defining the panel. It is a required option.


Examples

    . tsset id time
    . panelthin, min(5) gen(OK)
    . browse id time OK
    . keep if OK


Author

    Nicholas J. Cox, Durham University, UK
    n.j.cox@durham.ac.uk


Acknowledgments

    This problem was suggested by Rajesh Tharyan on Statalist.
    http://www.stata.com/statalist/archive/2008-05/msg00772.html

    Leny Matthew signalled a bug in an earlier version.


Also see

    On line: help for tsset