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RegisterGive sequence a chance [General Statistics]
Dear Stefano,
Not at least: Occurred simply by chance! Since and if it is extremely unlikely. See:
Stephen Senn, Giuseppina D’Angelo, and Diane Potvin
"Carry-over in cross-over trials in bioequivalence: theoretical concerns and empirical evidence"
Pharmaceut. Statist. 2004; 3: 133–142
But I guess, you know that?
Astonishing enough this is already mentioned in the 1997 FDA guidance:
"IV. Sequence effect
... Even if there were no true sequence effect, no unequal residual effect (aka carryover) and no period-by-treatment statistical interaction, approximately ten out of every hundred standard two-treatment crossover studies would be likely to show an apparent sequence effect, if the testing is carried out at the ten percent level of significance. ..."
Like Helmut I'm convinced that this is definitely a historical leftover.
But regulated by law. Because we/other/people[1] tend to take guidances in the field of medical research as law.
[1] Please delete where inapplicable.
❝ Probably, if we assume that carryover of higher order are extremely unlikely, its interpretation is analogous to that given in 2x2 design.
Not at least: Occurred simply by chance! Since and if it is extremely unlikely. See:
Stephen Senn, Giuseppina D’Angelo, and Diane Potvin
"Carry-over in cross-over trials in bioequivalence: theoretical concerns and empirical evidence"
Pharmaceut. Statist. 2004; 3: 133–142
But I guess, you know that?
Astonishing enough this is already mentioned in the 1997 FDA guidance:
"IV. Sequence effect
... Even if there were no true sequence effect, no unequal residual effect (aka carryover) and no period-by-treatment statistical interaction, approximately ten out of every hundred standard two-treatment crossover studies would be likely to show an apparent sequence effect, if the testing is carried out at the ten percent level of significance. ..."
❝ ... What I am really interested in is the rationale behind this "common practice".
Like Helmut I'm convinced that this is definitely a historical leftover.
But regulated by law. Because we/other/people[1] tend to take guidances in the field of medical research as law.
[1] Please delete where inapplicable.
—
Regards,
Detlew
Regards,
Detlew
Complete thread:
- Is the sequence effect mandatory? vezz 2009-12-09 21:52
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- Is the sequence effect mandatory? Pankaj Mishra 2009-12-10 07:21
- Sequence effect and 90% CI d_labes 2009-12-10 09:24
- Is the sequence effect mandatory? d_labes 2009-12-10 09:01
- Is the sequence effect mandatory? vezz 2009-12-10 11:02
- Treatment by period interaction d_labes 2009-12-10 16:43
- Old farts Helmut 2009-12-10 16:55
- Old farts vezz 2009-12-10 18:10
- New brooms Helmut 2009-12-10 19:19
- Give sequence a chanced_labes 2009-12-11 09:42
- Give history a chance Helmut 2009-12-11 13:40
- Old farts? d_labes 2009-12-11 09:09
- Young farts... Helmut 2009-12-11 13:51
- Old farts vezz 2009-12-10 18:10
- Old farts Helmut 2009-12-10 16:55
- Treatment by period interaction d_labes 2009-12-10 16:43
- Is the sequence effect mandatory? vezz 2009-12-10 11:02
- Is the sequence effect mandatory? Pankaj Mishra 2009-12-10 07:21
Ing. Helmut Schütz