Re: st: Wald interval and the WSJ

[David Airey <david.airey@Vanderbilt.Edu>]

.

Not having read the original study, it seems like this is a methods  
comparison study, where the old stent is considered a gold standard,  
and the new one has to perform as good or better than it for its  
better handling qualities to be useful. Graham Dunn's text,  
Statistical Evaluation of Measurement Errors, has a chapter on binary  
endpoints, but the introduction suggests it doesn't cover multinomial  
categorical endpoints...

-Dave
On Aug 14, 2008, at 10:08 AM, Maarten buis wrote:


> --- David Airey <david.airey@Vanderbilt.Edu> wrote:
> > And also the article doesn't emphasize effect size, which might make
> > the quibbling over p values moot too.
> Actually, the point estimate seems to suggest that the new stent does
> better then the old one, if I read the original article
> (http://content.onlinejacc.org/cgi/content/full/49/16/1676) correctly,
> and I know absolutely nothing about cardiology other than that a
> working hart is sorta crucial in staying alive.
>
> I read this article as follows: The thing under study is how well two
> types of stents prevent a thing called TVR (target vessel
> revascularization) which is apperently a bad thing. In the group with
> old stents this occured 68 times out of 855 (7.95%), while in the  
> group
> with new stents this occured 67 out of 956 times (7.01%). The purpose
> of this study is to test the hypothesis that the proportion new -
> porportion old > .03 .
>
> I have been looking around if I could reproduce the tests reported in
> the Wall Street Journal using Stata, but remained unsuccesful. This
> probably says more about me than about Stata, because statistically
> this is also unfamiliar terain for me, as I almost always do some sort
> of regression, moreover if I where to look at tests like these I would
> probably prefer odds ratios rather than risk differences.
>
> -- Maarten
>
> -----------------------------------------
> Maarten L. Buis
> Department of Social Research Methodology
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