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From |
Austin Nichols <austinnichols@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Missingness |

Date |
Tue, 28 Aug 2012 09:51:02 -0400 |

Brendan Churchill et al.: The original post is far from clear: is the missingness in LHS or RHS vars, or both? Was a dummy for missingness in a RHS variable X created and missing X recoded to zero so the dummy captures the difference in mean outcomes conditional on other variables between missing X and nonmissing X cases, which is known to be a problematic approach, or was missing X never recoded so the dummy is always zero in sample (and therefore collinear with the constant)? In any case, the manual entry on -mi- is a good place to start, though it does not mention an entirely different (no imputation) approach: treat missing data as survey nonresponse and use a propensity score reweighting method. See e.g. http://www.stata-journal.com/sjpdf.html?articlenum=st0136_1 and references therein. On Tue, Aug 28, 2012 at 10:20 AM, Richard Williams <richardwilliams.ndu@gmail.com> wrote: > At 02:42 AM 8/28/2012, Brendan Churchill wrote: >> >> Dear Statalist Users >> >> I am using some ordinal variables, which have some numeric missing values, >> in a multilevel model. In some previous research, I have seen researchers >> include a 'Missing' independent variable in their model to account for some >> of the 'missingness' - or rather to control for the missing values, but I >> don't quite understand how to do it in Stata or even if that's a good way to >> do it. I've tried to make a binary variable in which the missing values are >> coded 1 and the rest of the values are coded 0 but the model rejects this >> because it's collinear. >> >> Is this how you do it? Or is there a variable for the entire data set that >> is created to account for all missing variables? > > > In his green Sage book, "Missing Data", Paul Allison explains why this is > usually (albeit not always) a bad idea. I briefly summarize the argument on > pp. 4-5 of > > http://www.nd.edu/~rwilliam/xsoc63993/l12.pdf * * 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**:**st: Missingness***From:*Brendan Churchill <Brendan.Churchill@utas.edu.au>

**Re: st: Missingness***From:*Richard Williams <richardwilliams.ndu@gmail.com>

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