Re: PDF File of CMAJ paper "categorisation not a bad thing"
Posted by
Martin Holt-2 on
Jun 16, 2011; 5:37pm
URL: http://spssx-discussion.165.s1.nabble.com/PDF-File-of-CMAJ-paper-categorisation-not-a-bad-thing-tp4491777p4496064.html
The paper recommends performing an initial *exploratory* analysis using categorisation to identify those very circumstances when categorisation would be the best way forward.
If the analyst already has that information then, yes, it would be expected that the categorical approach would be the exception rather than the rule.
But if not, the exploratory analysis would identify some instances when the categorical data approach would be optimal. You'd only know by first checking it out.
So does it come down to saving effort....most of the time you'll be OK....which (a) doesn't seem professional to me, and (b) is not the argument usually given for only doing continuous data analysis.
I'm aware that this position goes against the recommendations of the majority (well, asks for an initial exploratory analysis), and that's why I disseminated the reference...it is very persuasive.
Best Regards,
Martin Holt
Medical Statistician
From: "Swank, Paul R" <[hidden email]>
To: "[hidden email]" <[hidden email]>; "[hidden email]" <[hidden email]>
Sent: Wed, 15 June, 2011 17:56:07
Subject: RE: PDF File of CMAJ paper "categorisation not a bad thing"
However, I think it should be pointed out that this is the exception rather than the rule. It should not be seen as a justification for categorizing contiuous data in general, nut only in certain circumstances.
Dr. Paul R. Swank,
Professor
Children's Learning Institute
University of Texas Health Science Center-Houston
From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of Martin Holt
Sent: Wednesday, June 15, 2011 11:07 AM
To: [hidden email]
Subject: PDF File of CMAJ paper "categorisation not a bad thing"
A couple of days ago I posted a comment that a case could be made for first performing categorisation before doing just the continuous analysis (as is always said to be required), as the data might have an unusual shape (eg BMI is parabolic).
I've been asked to supply a copy of the CMAJ paper that makes this case. So I've scanned it in as a PDF document, and if anyone else wants a copy please contact me offlist on [hidden email] and I'll duly send one.
Martin Holt
Medical Statistician |