Re: [R] How to intepret a factor response model?

From: Peter Flom <flom_at_ndri.org>
Date: Wed 04 May 2005 - 22:08:34 EST

>>> Maciej Blizi(Bński <m.blizinski@wsisiz.edu.pl> 5/4/2005 6:02:14 AM >>>
<<<
I'm trying to analyze a survey. Most of the variables are of factor type, with values for example {"no_at_all", "a_little", "mostly", "a_lot"}.
>>>

In that case, you probably want to look at ordinal logistic regression. This is covered in numerous texts, one good one which uses R is Harrell's Regression Modeling Strategies (an excellent book in other regards, as well).

Another book which might be useful (although not R specific) isLong's Regression Models for Categorical and Limited Dependent Variables

<<<
I thought about mapping those answers to numbers, but I didn't know what numbers should I assign them to: {1, 2, 3, 4} (linear) or maybe {1, 2, 4, 8} (exponential)? So I rather tried to analyze the original factor survey data.

Multinomial factor response wasn't covered in the lectures in my school so I'm trying to use my intuition and trial/error technique (please forgive me :-) ).
>>>

Using your intuition and trial and error seems to me to be a way to guarantee lots of trials and lots of errors, but not necessarily to guarantee success. You might want to consult a statistician before proceeding; you certainly want to consult a text.

HTH Peter

Peter L. Flom, PhD
Assistant Director, Statistics and Data Analysis Core Center for Drug Use and HIV Research
National Development and Research Institutes 71 W. 23rd St
www.peterflom.com
New York, NY 10010
(212) 845-4485 (voice)
(917) 438-0894 (fax)

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