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From |
Maarten buis <maartenbuis@yahoo.co.uk> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: mean, mode or median for missing values |

Date |
Wed, 3 Feb 2010 09:09:46 +0000 (GMT) |

--- On Wed, 3/2/10, Richard Williams wrote: > If you are going to use it as an > independent variable, do you plan on treating it as > continuous? If so, you wouldn't be the first person in > the world to do so and plugging in a mean or an imputed > regression estimate becomes more reasonable. I'll have to disagree with that. Imputing the dependent variables with mean values will seriously distort the associations you are going to find, as can be seen in the example below: *---------- begin example ------------ // create some data drop _all set obs 200 gen x = rnormal() gen y = x + .5*rnormal() // create missing values gen y2 = y in 20/l // impute with mean values sum y2 replace y2 = r(mean) if y2==. // display the concequences scatter y2 x in 20/l || /// scatter y2 x in 1/19, /// legend(order(1 "observed" 2 "imputed")) *------------ end example ------------ ( For more on how to use examples I sent to statalist see: http://www.maartenbuis.nl/stata/exampleFAQ.html ) For a solution Jet should consider the answers to Jet's question of yesterday: http://www.hsph.harvard.edu/cgi-bin/lwgate/STATALIST/archives/statalist.1002/date/article-71.html http://www.hsph.harvard.edu/cgi-bin/lwgate/STATALIST/archives/statalist.1002/Date/article-70.html Hope this helps, Maarten -------------------------- Maarten L. Buis Institut fuer Soziologie Universitaet Tuebingen Wilhelmstrasse 36 72074 Tuebingen Germany http://www.maartenbuis.nl -------------------------- * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**References**:**Re: st: mean, mode or median for missing values***From:*Richard Williams <Richard.A.Williams.5@ND.edu>

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