Bioequivalence and Bioavailability Forum

s2wR != mse, FDA != EMA [General Sta­tis­tics]

posted by Helmut  – Vienna, Austria, 2017-03-06 14:40 (2606 d 11:34 ago) – Posting: # 17138
Views: 17,704

Hi VStus,

❝ ❝ 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 s²_wT 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 CV_wT < CV_wR. The CRO refused to calculate CV_wT (“… 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.

—
Dif-tor heh smusma 🖖🏼 Довге життя Україна! 
Helmut Schütz


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Science Quotes

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 != mse, FDA != EMA VStus 2017-03-04 21:41
                      • s2wR != mse, FDA != EMAHelmut 2017-03-06 13:40