Bioequivalence and Bioavailability Forum 10:26 CEST

Main page Policy/Terms of Use Abbreviations Latest Posts

 Log in |  Register |  Search

The mysterious ρ -between or within studies [General Sta­tis­tics]

posted by d_labes - Berlin, Germany, 2018-02-11 15:57  - Posting: # 18395
Views: 4,198

Dear Helmut! Dear all!

» Current state of affairs about the mysterious ρ

That's not the whole truth about the state of affairs :no:.
The question is: Correlation of treatment differences between studies or within studies.

For the latter I recall you two references:
Phillips KF.
Power for Testing Multiple Instances of the Two One-Sided Tests Procedure
Int J Biostat. 2009;5(1):Article 15. doi:10.2202/1557-4679.1169

Hua SY, Xu S, D’Agostino RB Sr.
Multiplicity adjustments in testing for bioequivalence
Stat Med. 2015;34(2):215–31. doi:10.1002/sim.6247

Quote from Kem Phillips:
"The correlation will usually be difficult to estimate, unless a similar experiment has been conducted...".
That smells for me like within a study.

Definition in Hua et al., Section 2, clearly is within a study. Although Ben doubt the correctness of the formulas for ρ given in that paper. Note further that the observed alpha-inflation in that paper is crap. The IUT principle protects us from the need to adjust alpha.



Complete thread:

Back to the forum Activity
 Mix view
Bioequivalence and Bioavailability Forum |  Admin contact
18,761 posts in 3,996 threads, 1,265 registered users;
online 16 (0 registered, 16 guests [including 9 identified bots]).

The purpose of models is not to fit the data,
but to sharpen the questions.    Samuel Karlin

BEBAC Ing. Helmut Schütz