Bioequivalence and Bioavailability Forum

Higher order cross-over with ordinal response? [Nonparametrics]

posted by d_labes  – Berlin, Germany, 2010-06-30 18:16 (5047 d 12:59 ago) – Posting: # 5580
Views: 7,920

Dear Shri,

I presume this is a 4-period crossover study with four treatments, right?

Response is ordinal since your values are ordered categories.

You are interested in the differences (or equivalence?) between the treatments a, b, c and d, right?

I myself hadn't any such complicated, not an every-day-analysis to do in my career, thanks God . It's therefore out of my feasibility to point you to the right statistical method.

But I have some tips for you (but only if my presumptions are fulfilled):

• Treat your ordered categories (ranks) as metric (of course they are not ) and use them in the ordinary evaluation via parametric ANOVA. This is what Helmut has suggested in this thread regarding non-parametric evaluation of tmax. This will give a rough "feeling" for treatment differences.
  
  
• Read Chapter 6 "Analysis of Categorical Data" in
  Byron Jones, Michael G. Kenward
  "Design and Analysis of Cross-Over Trials"
  CHAPMAN & HALL/CRC
  Boca Raton, London New York Washington, D.C. (2003)
  Second Edition
  
  Read the paper
  Ezzet, F. and Whitehead, J.
  "A random effects model for ordinal response from a cross-over trial"
  Statistics in Medicine 10, 901-907 (1991)
  I'm not totally aware but it seems the keyword is "Logistic regression".
  
  And last but not least with the keywords from the subject line of this post.
  
  
• Consult a statistician of your very confidence who has "The power to know" with such a data analysis and outsource this analysis .
  

Hope this helps.

Complete thread:

• help shri 2008-08-20 11:06 
  • n x k contingency table? Jaime_R 2008-08-20 12:03
  • help ElMaestro 2008-08-20 12:29
    • help Jaime_R 2008-08-20 12:39
    • help statistician 2010-06-30 14:26
  • help martin 2008-08-20 12:58
    • help shri 2008-08-20 13:26
      • help martin 2008-08-20 14:14
  • Higher order cross-over with ordinal response?d_labes 2010-06-30 16:16