## Simulating studies in Excel not possible [Power / Sample Size]

Hi dshah,

» I would like to know about any available excel tool for sample size calculation for NTI by FDA method.
» I am asking this as many times- tools like R, Gpower etc. requires installation of software which is not permissible by many firms/organization.

Sorry, you have to convince your paranoic IT department.
The package PowerTOST is used in many companies and by regulatory agencies as well. The FDA’s Donald Schuir­mann performed his simulations in S-Plus, (‼), and APL.*

Background: For all reference-scaled approaches (the EMA’s ABEL, the FDA’s RSABE and NTID) you have to simulate studies. To get a stable result 100,000 are required. Even if you manage it to simulate subjects in Excel (a nutjob’s work but in principle doable), you will hit even in the current version of Excel the maximum number of rows (220 = 1,048,576). In other words, you can’t simulate more than 10 subjects…

• Schuirmann DJ. Evaluation of Scaling Approaches to Demonstrate BE of NTI Drugs – OGD Simulation Efforts. Advisory Committee for Pharmaceutical Science and Clinical Pharmacology. 26 July, 2011.  Archive-It (p.57–100 of the PDF).

Dif-tor heh smusma 🖖
Helmut Schütz

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