s2wR != mse, FDA != EMA [General Statistics]
Hi VStus,
No agency asks for s²wT in the context of RSABE or ABEL (the FDA’s RSABE for NTIDs is another story but requires a 4-period full replicate anyhow). Hence, why should one report it?
I never understood why one would opt for the partial replicate. Does this equation hold?
IMHO, at least in pilot studies full replicates are preferable (see there). I once struggled with a Romanian CRO. The sponsor decided to perform a 4-period full replicate in order to possibly end up with a smaller sample size of the pivotal study if CVwT < CVwR. The CRO refused to calculate CVwT (“… because not in accordance with the SAS-code given in the Q&A.”)… Oh boy! Only after the sponsor threatened to go with another CRO, they gave in.
❝ ❝ But s2wR = MSE
is not necessarily true in all cases, although it is in many cases a reasonable assumption.
❝ And s2wR != s2wT in most cases. Maybe that's the reason why 2x3x3 design is still so popular. It's not possible to assess s2wT...
No agency asks for s²wT in the context of RSABE or ABEL (the FDA’s RSABE for NTIDs is another story but requires a 4-period full replicate anyhow). Hence, why should one report it?

I never understood why one would opt for the partial replicate. Does this equation hold?
Partial replicate = lack of statistical knowledge + “we want only three periods” + given in the FDA’s guidance / the EMA’ Q&A-document (as an example)?
IMHO, at least in pilot studies full replicates are preferable (see there). I once struggled with a Romanian CRO. The sponsor decided to perform a 4-period full replicate in order to possibly end up with a smaller sample size of the pivotal study if CVwT < CVwR. The CRO refused to calculate CVwT (“… because not in accordance with the SAS-code given in the Q&A.”)… Oh boy! Only after the sponsor threatened to go with another CRO, they gave in.
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Complete thread:
- Confidence Interval for Transformed data Unbalanced study usfda_emea 2007-03-06 14:39 [General Statistics]
- CI for Transformed data Unbalanced study Helmut 2007-03-06 16:46
- CI for Transformed data Unbalanced study drshiv 2007-03-06 18:49
- CI for Transformed data Unbalanced study usfda_emea 2007-03-07 06:21
- CI for Transformed data Unbalanced study Helmut 2007-03-07 12:04
- CI for Transformed data Unbalanced study usfda_emea 2007-03-07 12:34
- CI for Transformed data Unbalanced study Ohlbe 2014-07-30 15:04
- LSM limbo Helmut 2014-07-31 02:54
- LSM limbo Ohlbe 2014-07-31 09:47
- 90% CI limbo VStus 2017-03-01 14:07
- RSABE ⇒ ABEL Helmut 2017-03-03 13:34
- RSABE ⇒ ABEL VStus 2017-03-03 15:31
- s2wR != mse, FDA != EMA d_labes 2017-03-04 14:49
- s2wR != mse, FDA != EMA ElMaestro 2017-03-04 19:13
- s2wR from ISC in FDA approach d_labes 2017-03-05 12:18
- s2wR from ISC in FDA approach ElMaestro 2017-03-05 13:50
- s2wR from ISC in FDA approach d_labes 2017-03-05 12:18
- s2wR != mse, FDA != EMA VStus 2017-03-04 21:41
- s2wR != mse, FDA != EMAHelmut 2017-03-06 13:40
- s2wR != mse, FDA != EMA ElMaestro 2017-03-04 19:13
- s2wR != mse, FDA != EMA d_labes 2017-03-04 14:49
- RSABE ⇒ ABEL VStus 2017-03-03 15:31
- RSABE ⇒ ABEL Helmut 2017-03-03 13:34
- LSM limbo Helmut 2014-07-31 02:54
- CI for Transformed data Unbalanced study Helmut 2007-03-07 12:04
- CI for Transformed data Unbalanced study Helmut 2007-03-06 16:46