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From |
"Svend Juul" <[email protected]> |

To |
<[email protected]> |

Subject |
Re: st: My last word on strange world |

Date |
Fri, 11 Jan 2008 12:40:43 +0100 |

So many trying to get the last word on a problem that won't go away. I read Bill Gould's comments as a bit softer than they used to be, but I may be mistaken. Bill writes: "... the problem of missing values and the number line are inherent" Yes, but does that make it necessary to - let (x) evaluate to true if x is missing: . gen y=1 if x - let (x>100) evaluate to true if x is missing: . gen y=1 if x>100 Obviously, some decision was needed. The decision made is perfectly logical, but the following alternative is equally logical and much more in line with the expectations of ordinary users: - let (x) evaluate to false if x is missing - let (x>100) evaluate to false if x is missing - let (x==100) evaluate to false if x is missing - let (x<100) evaluate to false if x is missing - let (x==.) evaluate to true if x is . (missing) Nick Cox asks: "What do you consider appropriate Stata behaviour for . list x if x > 42 . regress z y if x > 42" This is easy: I consider it appropriate to omit observations with x missing in both situations. I do not care about the internal value of missings (this is why I bought a statistical package program), and I see no problem in the way -sort- handles them. Bill Gould: "The observations containing missing values need to be easy to identify and classify". Don't the missing() function and egen's rowmiss() and rownonmiss() do that perfectly? Last word? Hardly. Svend __________________________________________ Svend Juul Institut for Folkesundhed, Afdeling for Epidemiologi (Institute of Public Health, Department of Epidemiology) Vennelyst Boulevard 6 DK-8000 Aarhus C, Denmark Phone: +45 8942 6090 Mobile: +45 2634 7796 Email: [email protected] __________________________________________ * * 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: st: My last word on strange world***From:*SamL <[email protected]>

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