## Requesting data for a publication 📥 ♻️ 🚀 [General Statistics]

Dear all,

we are collecting data for a publication about the annoying ‘Group-by-Treatment interaction’ (for some thoughts see this article).

Below what we have so far in a meta-analysis of multi-

To make a long story short: As expected, significant Group-by-Treatment interactions were detected at approximately the level of the test (0.05) and below the upper 95% significance limit of the binomial test. Hence, based on our observations in well-controlled studies likely they are mere ‘statistical artifacts’,

At a recent BE workshop

Any type of comparative BA study (BE, food-effect, DDI, dose-proportionality) is welcome.

Of course, data will be treated strictly confidential and not published . The preferred data format is CSV (though xls(x), ODS, SAS XPT or Phoenix project files would serve as well).

Columns (any order is fine):

No cherry-picking, otherwise we will fall into the trap of selection bias and the outcome will be useless. Hence, if you decide to provide data, please do so irrespective of whether you ‘detected’ a significant Group-by-Treatment interaction or not.

We are primarily working on 2×2×2 crossover designs. However, if you have data of replicate designs, fine as well. In Higher-Order crossover designs indicate which of the treatments is the test and the reference.

If possible, give the analyte. Once we have enough data sets, we will perform sub-group analyses.

So far we have only data of one multi-

THX in advance!

we are collecting data for a publication about the annoying ‘Group-by-Treatment interaction’ (for some thoughts see this article).

Below what we have so far in a meta-analysis of multi-

*group*studies:To make a long story short: As expected, significant Group-by-Treatment interactions were detected at approximately the level of the test (0.05) and below the upper 95% significance limit of the binomial test. Hence, based on our observations in well-controlled studies likely they are mere ‘statistical artifacts’,

*i.e.*, false positives. The Kolmogorov–Smirnov tests were not significant, accepting the expected standard uniform distribution of \(\small{p(G\times T)}\).At a recent BE workshop

^{1}I had a conversation with a prominent member of the FDA. She told that the agency tests the Group-by-Treatment interaction at the 0.05 level, thus reducing the false positive rate observed at the previously used 0.1 level. But then she also said»*We often see not only p-values just below 0.05, but also some with 0.0001…*«

*p*-value as the*probability*that the null hypothesis is true (or the alternative hypothesis is false).^{2}The outcome of a level \(\small{\alpha}\)-test is dichotomous: Hypotheses are considered true or false, not something that can be represented with a probability.Any type of comparative BA study (BE, food-effect, DDI, dose-proportionality) is welcome.

Of course, data will be treated strictly confidential and not published . The preferred data format is CSV (though xls(x), ODS, SAS XPT or Phoenix project files would serve as well).

Columns (any order is fine):

- Company or individual (text)

- Study code (text)

- Analyte (text) if you don’t want to give this information, use
`not spec. X`

, where`X`

is an integer`1`

… number of analytes

- Design (
`2x2x2`

,`3x6x3`

,`3x3`

,`4x4`

,`2x2x4`

,`2x2x3`

,`2x3x3`

)

Simple crossover, 6-sequence 3-period Williams’ design, 3-period Latin Squares, 4-sequence 4-period Williams’ design or 4-period Latin Squares, 2-sequence 4-period full replicate, 2-sequence 3-period full replicate, partial replicate; no parallel design

- Drug (integer)
`1`

… number of analytes

- Subject (integer or text) min(
`n`

) … max(`n`

); missings due to dropouts not a problem

- Group or Site (integer)
`1`

… number of groups / sites

- Sequence (character or integer), e.g.,
`TR`

,`RT`

or`AB`

,`BA`

or`1`

,`2`

(simple crossover),*e.g.*,`TRTR`

,`RTRT`

or`TRT`

,`RTR`

(full replicate designs),`TRR`

,`RTR`

,`RRR`

(partial replicate design),`ABC`

,`BCA`

,`CAB`

(Latin Squares),`ABC`

,`ACB`

,`BAC`

,`BCA`

,`CAB`

,`CBA`

(Williams’ design)

Essentially any kind of coding is possible, as long as it is unambiguous.

- Treatment (character) mandatory
`T`

or`R`

(*not*`A`

or`B`

)

- Period (integer)
`1`

… number of periods

*AUC*(numeric); for single dose*AUC*_{0–t}or*AUC*_{0–72}, for multiple dose*AUC*_{0–τ}.

Missing values should be coded with`NA`

(preferred) or`Missing`

.

*C*_{max}(numeric)

- Interval (integer) days separating groups; only if equal across groups

- Sex (character)
`f`

or`m`

No cherry-picking, otherwise we will fall into the trap of selection bias and the outcome will be useless. Hence, if you decide to provide data, please do so irrespective of whether you ‘detected’ a significant Group-by-Treatment interaction or not.

We are primarily working on 2×2×2 crossover designs. However, if you have data of replicate designs, fine as well. In Higher-Order crossover designs indicate which of the treatments is the test and the reference.

If possible, give the analyte. Once we have enough data sets, we will perform sub-group analyses.

So far we have only data of one multi-

*site*study. If you could share some data, great.THX in advance!

- Medicines for Europe.
*2*Brussels. 26 April 2023.^{nd}Bioequivalence Workshop. Session 2 – ICH M13 – Bioequivalence for IR solid oral dosage forms.

- Wasserstein RL, Lazar NA.
*The ASA’s Statement on p-Values: Context, Process, and Purpose.*Am Stat. 2016; 70(2): 129–33. doi:10.1080/00031305.2016.1154108.

—

Helmut Schütz

The quality of responses received is directly proportional to the quality of the question asked. 🚮

Science Quotes

*Dif-tor heh smusma*🖖🏼 Довге життя Україна!_{}Helmut Schütz

The quality of responses received is directly proportional to the quality of the question asked. 🚮

Science Quotes

### Complete thread:

- Requesting data for a publication 📥 ♻️ 🚀Helmut 2021-04-08 17:09 [General Statistics]