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From |
"Nick Cox" <n.j.cox@durham.ac.uk> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
RE: st: RE: A modest proposal - missing data doesn't count |

Date |
Tue, 15 Jun 2010 18:08:25 +0100 |

Paradoxical though it may seem, Allan has got to produce a stronger argument before it can judged exactly how good his proposal is. To that extent I agree with David. Otherwise I remain sceptical, while acknowledging fully that sceptical attitude differs from logical debunking. Although it is difficult to demonstrate here, it should be underlined, from e.g. discussions at users' meetings, that StataCorp have thought long and hard about better solutions to this over many years. The absence of a solution that satisfies all is not indicative of absence of effort to find such a solution. Nick n.j.cox@durham.ac.uk David Bell I am in principle supportive of this new -value- expression. I get bit periodically and the various workarounds are sometimes inelegant. But some of the counterarguments seem potentially fatal. However, assertions that a working solution _cannot_ exist have not yet been established. In the spirit of seeing whether there is a resolution to this discussion of a potential -value- expression, I see two steps that are brought up by the discussion: (1) what is a proposed description of what -value()- should do, and (2) what are the various special situations and combinations of special situations, and how would the proposed deal with them? Could there be a way that this new expression could correspond to people's intuitive understandings in a way that, while having perhaps its own issues, would bite less than the - >10 - problem bites? On Jun 15, 2010, at 12:40 PM, Austin Nichols wrote: > Martin-- > I agree. In particular the treatment of p&q and p|q in the presence > of one missing value should worry anyone who actually uses data; this > is something that requires careful thought in any specific instance, > depending on what one is trying to estimate. > > Allan-- > Both x<10 and x>10 can be affected by presence of missings in x; think of > . gen dummy=(x<10) > for example. No solution is perfect, and the treatment in functions > like max() and sum(), or egen functions like rowtotal() etc., logical > expressions, algebra on variables, and so forth may be hard for some > users to internalize, but so would another "solution" create > difficulties, not always immediately obvious, and bound to trip up > those of us who are used to the current behavior (but still get > tripped up by the current behavior when we aren't careful). > > On Tue, Jun 15, 2010 at 6:53 AM, Martin Weiss <martin.weiss1@gmx.de> wrote: > <snip> >> I found the alternative approaches to missings presented in >> http://www.stata.com/meeting/uk08/KIMacD.presentation.ppt wholly >> unconvincing and worse than the current state. > <snip> >> -----Allan Reese----- >> It's so easy to forget that x<10 will not be affected by missing values >> but x>10 will be. It would be good to have software that guards against >> pitfalls rather than invites you in. > <snip> * * 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/

**Follow-Ups**:**Re: st: RE: A modest proposal - missing data doesn't count***From:*Phil Schumm <pschumm@uchicago.edu>

**References**:**Re: st: RE: A modest proposal - missing data doesn't count***From:*"Allan Reese (Cefas)" <allan.reese@cefas.co.uk>

**Re: st: RE: A modest proposal - missing data doesn't count***From:*Austin Nichols <austinnichols@gmail.com>

**Re: st: RE: A modest proposal - missing data doesn't count***From:*David Bell <dcbell@iupui.edu>

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