Software validation – again and again [Power / Sample Size]
❝ we have not yet finalized the SOP, and moreover we use the SAS Software procedure "PROC POWER" for the estimation of the sample size.
OK.
❝ But however we wanted it to be more accurate sample size for that we want to include the deletti tables.
I wonder why you were asking here for the Diletti tables. The reference is readily available in the manual of
Proc POWER
…Proc POWER
employs Owen’s Q-function1 – as does PowerTOST
by default. AFAIK, OwenQ
is a still undocumented function in SAS… Proc POWER
is available in SAS since v9.1 (2003). Hence, Diletti et al. wrote in 1991:The exact form of these integrals and an algorithm for their calculation has been provide by Owen; this algorithm has been implemented to create the figures and tables in this paper.
We don’t know which software and code they used. Edgar Diletti and Volker Steinijans are retired; ask Dieter Hauschke.❝ ❝ These tables […] are hopelessly behind state of the art!
❝ ❝ ❝ NB, if you are interested in reference-scaling […]
❝
❝ Yes
For all reference-scaling methods you need simulations and have to write your own SAS-code. Expect run-times of many, many hours. The two Lászlós wrote their code in MATLAB, which is only slightly faster than SAS. Hence, for years they recommend
PowerTOST
themselves.❝ ❝ Hence, I strongly suggest […] package PowerTOST
.
❝
❝ yes we are thinking to opt this package. But however we have a concern whether regulatory will accept it or not.
❝ By then we are doubtfull of using this package.
Since
PowerTOST
is open source you (or an -expert) can perform a white-box validation. Additionally, PowerTOST
contains not only reference data sets from the literature but also scripts to validate your installation. See also this thread.Maybe you are interested in this document.2
❝ Sometime ago I have faced the concern regarding the Software validation from the regulatory.
Any software used in a GCP-environment has to be validated. Have you done that with SAS?* No, I don’t mean just IQ, OQ, PQ! Good luck with commercial software where the source code (allowing white-box validation) is not accessible. You could only perform cross-validation (black-box) with reference data sets. If you don’t have more than one software at hand, you have to believe (!) that what is reported for the reference data set is correct.
- Owen DB. A special case of a bivariate non-central t-distribution. Biometrika. 1965;52(3/4):437–46. doi:10.2307/2333696.
- The R Foundation for Statistical Computing. R: Regulatory Compliance and Validation Issues. A Guidance Document for the Use of R in Regulated Clinical Trial Environments. Vienna, March 2018. open access.
- Stephen Senn told me this story:
He discovered that after an update of SAS the Welch-Satterthwaite’s degrees of freedom (required in parallel designs with unequal group sizes and/or unequal variances) were faulty. Scary, cause such data sets are the rule in phase III. He phoned the SAS-Institute and got the responsible software engineer on the line. After inspecting the source within minutes he confirmed the bug. However, it took SAS half a year to roll out a patch…
So much for that.
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:
- Deletti tables for sample size sury 2019-03-19 12:22 [Power / Sample Size]
- Of historic(al) interest only Helmut 2019-03-19 13:27
- Of historic(al) interest only sury 2019-03-20 05:04
- Software validation – again and againHelmut 2019-03-20 12:12
- Software validation – again and again nobody 2019-03-20 16:20
- Fiaker und Apfelstrudel Helmut 2019-03-20 16:35
- Fiaker und Apfelstrudel nobody 2019-03-20 17:34
- Fiaker und Apfelstrudel Helmut 2019-03-20 17:54
- Fiaker und Apfelstrudel d_labes 2019-03-20 18:39
- Fiaker und Apfelstrudel ElMaestro 2019-03-20 22:09
- Fiaker und Apfelstrudel Helmut 2019-03-20 17:54
- Fiaker und Apfelstrudel nobody 2019-03-20 17:34
- Fiaker und Apfelstrudel Helmut 2019-03-20 16:35
- White-box validation mittyri 2019-03-20 21:09
- White-box validation Helmut 2019-03-21 00:19
- Software validation – again and again nobody 2019-03-20 16:20
- Power of Proc Power d_labes 2019-03-20 18:37
- Software validation – again and againHelmut 2019-03-20 12:12
- Of historic(al) interest only sury 2019-03-20 05:04
- Of historic(al) interest only Helmut 2019-03-19 13:27