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Re: A tree based lack of fit test

Posted by Mike on Jun 17, 2013; 4:06pm
URL: http://spssx-discussion.165.s1.nabble.com/A-tree-based-lack-of-fit-test-tp5720764p5720769.html

A few points:
 
(1)  I believe that you are referring to the following reference:
http://onlinelibrary.wiley.com/doi/10.1002/sim.1750/abstract
It's a good idea to provide a complete reference, especially if
one wants to know if it is highly cited or not.
 
(2) In scholar.google.com, there are only 5 sources citing this
article and only one appears to be journal article (Theetan et al 2007).
From their presentation, their justification does not seem to be
very convincing to me but what do I know.  I note that both the
Moons et al paper and the Theetan et al paper come from institutions
in Belgium and perhaps this is a procedure that has some local
preference (a wide acceptance would be indicated by a larger
number of citation and from institutions in different locations).
 
(3)  If you have read the Moons et al paper, early on they state
that there are various nonparametric analyses that can be used to
assess fit in logistic regression when one has continuous predictors.
Only the Hosmer & Lemeshow test makes use of the Pearson
chi-square while the nonparametric tests don't -- Moons et al
propose a test that also makes use of the Chi-square which seems
to be their main argument for their test but both produce approximate
results.  The Tree-based (TB) approach appears to behave better
than the Hosmer & Lemeshow test (e.g., better power, etc.) but
one will have to spend some time determining whether that is the
case for one's dataset.

(4)  Moons et al state at the end of their article that an S-plus program
is available from the authors but you have to contact them as they
don't provide a website address to access the S-plus code.  This raises
the question of whether one can only do their analyses in S-plus (do you
have access to it?) or can it be translated into SPSS?  Translating
it into SPSS and testing it could be a time-consuming process unless
you have someone really skilled doing the work -- I hear that David
Marso is good at this, if you have the money. ;-)
 
So, you have to ask yourself:  does the Moons et al TB procedure
answer the questions you want answered better than other procedures
(e.g., the Hosmer & Lemeshow test or one of the other nonparametric
procedures)?  If so, then you might want to invest the time and effort
in setting up the TB procedure in whatever fashion your resources allow.
You might want to ask your dissertation advisor about this and/or see
if you can find someone who has actually used this procedure and what
ask them if it is really what you need.  However, it seems to me that not
many people may have used this procedure, so finding an appropriate
consultant might be difficult.
 
It would be interesting to hear what others have to say about this.
 
-Mike Palij
New York University
[hidden email]
 
 
----- Original Message -----
From: [hidden email]
To: [hidden email]
Sent: Monday, June 17, 2013 11:03 AM
Subject: A tree based lack of fit test

 
 Hi everyone,

 I am working on my dissertation and will be doing a multivariate logistical
 regression for my analysis.
 I have continuous co-variates and a dichotomous dependent variable.
 I came across the following reference:
 Moons, E., Aerts, M., & Wets, G. A tree based lack of fit test for multiple
 logistic regression.   The authors compare Tree based lack of fit to Hosmer and Lemeshow.
 Is this an accepted alternative to H & L?  I would appreciate any thoughts
 the you all may have.
 
Thank you so much
 
C. Mazzotta
Doctoral Candidate
UB
Buffalo, NY