I have learned a lot from this discussion. In this most recent go 'round
I did not think anyone was trying to have the last word. I thought each
person was providing *their* own *personal* last word on the matter. I
admit, some contributed a "really" last word after their first "last word"
statement. But I did not see anyone--save, perhaps, Svend?--who was
suggesting they were providing THE last word on the topic.
And now, I guess, me.
Perhaps this can be the last word on the topic for 2008?
Let's move on. Let's call this:
Done.
On Fri, 11 Jan 2008, Svend Juul wrote:
>
> 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]
> __________________________________________
>
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