Bioequivalence and Bioavailability Forum

Noise… [RSABE / ABEL]

posted by Helmut  – Vienna, Austria, 2014-07-22 15:31 (3948 d 22:20 ago) – Posting: # 13290
Views: 13,027

Dear Detlew,

❝ Where does the tremendous noise in your pictures came from?

Quick and dirty as ever; I set a different seed for every simulation. Looks better if keeping the same one:

❝ And Fig. 2 (as well as others) of the paper is with tremendous (arbitrary?) smoothing? Crossing of some of the curves seems to point in that direction. The plot form (continuous curves, without the points they have simulated) itself is suspicious IMHO.

Agree.

❝ BTW: Do you see any need to create a power.addon() in PowerTOST? Pedagogical?

I guess enthusiasts could already misuse* the – experimental – function power.2stage.GS() as I did. I tried alpha=c(0.05, 0.05) and n=c(n, n/2+(n/2)%%2). The modulo in the second part of the n-vector rounds up to the next even number be­cause I don’t like imbalanced studies. Example: n = 18, n/2 = 9, n/2+(n/2) mod 2 = 10.
power.addon() would be nice, of course.

BTW, the Japanese guidance states:

The add-on subject study should include at least one half of the number of subjects in the initial study.

I overlooked that until today (believing that n₂ is fixed at n₁/2). This opens the door to an infinite number of designs (adjusting for the observed CV, any power, even fully ad­ap­tive). Glad that I never dealt with submissions to Japan so far.

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• Due to the futility criterion in this function there are cases where the study stops after the first part. Anyhow, I saw inflation of ~7.55%.

—
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:

• EMA: α-inflation – the sus­pi­cion begins to mount Helmut 2014-07-21 02:04 
  • EMA: α-inflation – the sus­pi­cion begins to mount ElMaestro 2014-07-21 09:24
    • Why simulate a simple AB|BA at all? Helmut 2014-07-21 16:14
      • Why simulate a simple AB|BA at all? ElMaestro 2014-07-21 20:50
        • Fancy smoothing? Helmut 2014-07-21 23:13
          • Arbitrary smoothing? d_labes 2014-07-22 08:43
            • Noise…Helmut 2014-07-22 13:31
              • TSD Japonica… d_labes 2014-07-22 16:06
                • TSD Japonica… Helmut 2014-07-22 17:50
              • Noise debugged d_labes 2014-07-24 13:47
                • Noise debugged Helmut 2014-07-24 15:07
                  • Shit happens d_labes 2014-07-24 16:09
        • Commentary d_labes 2014-07-22 08:18
          • Commentary nobody 2014-09-15 08:24
            • Commentary Helmut 2014-09-15 10:12
        • IBE/PBE = Two-Stage Helmut 2014-09-29 03:33
          • IBE/PBE = Two-Stage ElMaestro 2014-09-29 15:16
            • Sequential Design = Inflation likely… Helmut 2014-09-30 15:03