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RegisterSo they implemented Pitman-Morgan [General Statistics]
Hello everybody and a nice evening.
I have to comment on the Release Notes of Phoenix WinNonlin 6.4 from August last year at the moment. In the "What's new" section I saw that Certara implemented tests for equal variances for parallel designs and also for 2x2 cross-over studies. And this is accompanied by some explanation in the handbook on how to proceed in case a significant value is observed (basically, you implement a random/repeated specification for period and group by formulation).
As I am not a statistician and, frankly, never came across a discussion of this test I tried to find out something about its importance in bioequivalence/rel. bioavailability.
Fortunately, after some unsuccessful searching in the net and this forum, I found some information in Chow & Liu 3rd edition (p.196) and, although I fail to understand most of the discussion
, that seems to imply, that this test is not only relevant in pop/ind equivalence (found it only for these in Hauschke, Steinijans & Pigeot) but also for testing the intra-individual variance in a simple 2x2x2 cross-over study (not inter!) for average BE. Uhm, however, the consequences of rejection of H0 seem to be missing.
Whatever, as a natural consequence, I tried to figure out whether the recommended adaptation of the evaluation as given for Phoenix WinNonlin actually has any effect on the (BE) result at all simply using recent data sets (as said, I don't understand the formula sufficiently, have to try and compare
).
I was not able to perform the testing for unequal variances, but some variabilities (for Reference or Test) at least "look" different.
And there was no effect at all in PE or CIs
. Thus, I wonder 
:
Best regards,
Steven.
I have to comment on the Release Notes of Phoenix WinNonlin 6.4 from August last year at the moment. In the "What's new" section I saw that Certara implemented tests for equal variances for parallel designs and also for 2x2 cross-over studies. And this is accompanied by some explanation in the handbook on how to proceed in case a significant value is observed (basically, you implement a random/repeated specification for period and group by formulation).
As I am not a statistician and, frankly, never came across a discussion of this test I tried to find out something about its importance in bioequivalence/rel. bioavailability.
Fortunately, after some unsuccessful searching in the net and this forum, I found some information in Chow & Liu 3rd edition (p.196) and, although I fail to understand most of the discussion
, that seems to imply, that this test is not only relevant in pop/ind equivalence (found it only for these in Hauschke, Steinijans & Pigeot) but also for testing the intra-individual variance in a simple 2x2x2 cross-over study (not inter!) for average BE. Uhm, however, the consequences of rejection of H0 seem to be missing.Whatever, as a natural consequence, I tried to figure out whether the recommended adaptation of the evaluation as given for Phoenix WinNonlin actually has any effect on the (BE) result at all simply using recent data sets (as said, I don't understand the formula sufficiently, have to try and compare
). I was not able to perform the testing for unequal variances, but some variabilities (for Reference or Test) at least "look" different.
And there was no effect at all in PE or CIs
. Thus, I wonder :- has such a test any meaning for the "final" outcome in BE testing, the estimate/CI of the ratio between treatments (probably my tests just showed no difference due to chance)?
- and if so, could the proposed workaround be communicated to EU authorities anyway (this is clearly not an "all effects fixed" situation)
- or is this for information only comparable to the testing for period and sequence effects?
Best regards,
Steven.
Complete thread:
- So they implemented Pitman-MorganRelaxation 2015-02-20 16:31
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- I would not apply pretesting Helmut 2015-02-20 18:56
- I would not apply pretesting Relaxation 2015-02-24 13:06
- I would gladly apply pretesting ElMaestro 2015-02-24 14:28
- Simulations feasible? Helmut 2015-02-24 16:05
- Mixed vs. fixed effects (mainly) Helmut 2015-02-24 14:51
- Mixed vs. fixed effects (mainly) Relaxation 2015-02-26 12:50
- I would gladly apply pretesting ElMaestro 2015-02-24 14:28
- I would not apply pretesting Relaxation 2015-02-24 13:06
- I would not apply pretesting Helmut 2015-02-20 18:56
Ing. Helmut Schütz