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DUPS: Stata module to identify and optionally remove duplicate observations


  • Nicholas J. Cox

    () (University of Durham)

  • Thomas Steichen



dups provides information about unique and duplicate observations in the dataset and, optionally, drops all duplicate observations. varlist is an optional variable list that determines which observations are duplicates (observations must match exactly on all variables in the list to be duplicates). If no varlist is given, then all variables in the dataset are used to determine duplicates. drop is a command line option that causes duplicate observations to be dropped from the dataset. Both terse and verbose options are available to modify the detail in the default output; terse gives bare minimum information; verbose lists detailed information about duplicate observations. This is version 1.0.3 of the software.

Suggested Citation

  • Nicholas J. Cox & Thomas Steichen, 1997. "DUPS: Stata module to identify and optionally remove duplicate observations," Statistical Software Components S322901, Boston College Department of Economics, revised 23 Sep 2001.
  • Handle: RePEc:boc:bocode:s322901
    Note: This module may be installed from within Stata by typing "ssc install dups". Windows users should not attempt to download these files with a web browser.

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    duplicate observations; drop; detect;


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