Really worth the efforts? [Two-Stage / GS Designs]
❝ this is a very eminent important post .
THX. Was mainly a kind of self-defense. If such an idea pops up in the future, I would just link to this post.
❝ ❝ […] we still need 105 simulations within every simulated study. This leads to ~1014 (110,000,000,000,000‼) simulations overall.
❝
❝ This is an optimistic (sic!) estimation […]
❝
❝ So let us estimate more pessimistically (but may be too optimistically) an additional factor of 4 (one for the power monitoring step + 3 for the sample size estimation) within each of the simulations […]
At least for “Type 1” designs, you need only one step – as you ingeniously have implemented it in
Power2Stage
. An estimated total sample size ≤ n1 implies power ≥ target. 
❝ Just to make your message crystal clear!
Yep. Whether it takes five or fifty years makes no difference in practice. It simply takes too long.
❝ If this all is necessary to be really done for a certain regulatory body (which one remains my secret ) remains an open question. As elsewhere said: Regulators are a bunch of strange people.
I think that it is justified if regulators ask for demonstration that the TIE is maintained. That’s their job.
Sponsors should learn that Two-Stage Design are not the jack of all trades device (
<span lang="de">
„eierlegende Wollmilchsau” </span>
) as they inadvertently believe. TSDs are fine in ABE to deal with an uncertain CV. This is not necessary if we apply scaling – which inherently takes care of higher than expected variability. If a study is powered for ABE, everything should be OK (well, cough, inflation in ABEL/RSABE – another story).Like in ABE the nasty thing is the ratio…
Dif-tor heh smusma 🖖🏼 Довге життя Україна!
![[image]](https://static.bebac.at/pics/Blue_and_yellow_ribbon_UA.png)
Helmut Schütz
![[image]](https://static.bebac.at/img/CC by.png)
The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes
Complete thread:
- TSDs for RSABE/ABEL Helmut 2015-05-06 02:17 [Two-Stage / GS Designs]
- TSDs for RSABE/ABEL nobody 2015-05-06 11:13
- TSDs for RSABE/ABEL Helmut 2015-05-06 11:55
- TSDs for RSABE/ABEL nobody 2015-05-06 12:26
- TSDs for RSABE/ABEL Helmut 2015-05-06 11:55
- TSDs for RSABE/ABEL ElMaestro 2015-05-06 12:31
- TSDs for RSABE/ABEL Helmut 2015-05-06 13:49
- TSDs for RSABE/ABEL - run-time d_labes 2015-05-08 20:47
- Really worth the efforts?Helmut 2015-05-10 01:11
- TSDs for RSABE/ABEL nobody 2015-05-06 11:13