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From |
"David E Moore" <davem@hartman-group.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
RE: Missing values [was: RE: st: simple question] |

Date |
Wed, 2 Jun 2004 16:54:35 -0700 |

Is it worth pointing out that SAS, which may be the most widely used stat package on the planet, uses missing value codes almost exactly the same way that Stata uses them. S-Plus uses an internal code (similar to old-style Stata's ".") and LIMDEP (at least at Version 6.0) used -999 to indicate missing. While I too find it sometimes convenient to define arbitrary values as missing in SPSS, this by no means is a universal approach and has even led to subtle errors when the missing codes were not properly defined (or handled) as missing. (Of course, I never made such errors, but I've heard plenty of stories....) Nevertheless, I personally prefer the SAS/Stata approach over the SPSS approach. I also agree that Stat/Transfer should endeavor to preserve unique missing value codes whenever possible, if it does not do so. > -----Original Message----- > From: owner-statalist@hsphsun2.harvard.edu > [mailto:owner-statalist@hsphsun2.harvard.edu]On Behalf Of Richard > Williams > Sent: Wednesday, June 02, 2004 2:41 PM > To: statalist@hsphsun2.harvard.edu > Subject: Re: Missing values [was: RE: st: simple question] > > > At 10:18 PM 6/2/2004 +0100, Nick Cox wrote: > >Perhaps you could expand on this. > > Sure. What I dislike is that, unlike other programs, Stata forces you to > recode the MD values from a data set. All those 7s, 9s, 99s, etc. will > have to be recoded to .a, .b, etc. The values you use for MD will not be > the same as the values in the published codebooks or that may be reported > by other users of the data who are using other programs. > > In SPSS, on the other hand, I would just say something like > > Missing Values X (77, 88, 99). > > This isn't a mega problem, but when Stata expanded its possible MD codes > I'd have rather seen it take an SPSS-type approach than the route it did > go. (On the other hand, I suppose you could argue that the rest of the > world should do things more like Stata.) > > The bigger problem (which is perhaps more of an issue with Stat/Transfer > than it is with Stata) is that distinctions between types of MD codes get > lost when converting from SPSS to Stata. I don't know whether this problem > is unique to Stata or occurs with other types of conversions as well, but I > would like to see software better address it, e.g. when there are multiple > MD codes in SPSS assign them to .a, .b, etc. in Stata. > > * > * For searches and help try: > * http://www.stata.com/support/faqs/res/findit.html > * http://www.stata.com/support/statalist/faq > * http://www.ats.ucla.edu/stat/stata/ > > * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**RE: Missing values [was: RE: st: simple question]***From:*Richard Williams <Richard.A.Williams.5@ND.edu>

**References**:**Re: Missing values [was: RE: st: simple question]***From:*Richard Williams <Richard.A.Williams.5@ND.edu>

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