[R] SAS or R software

Frank E Harrell Jr f.harrell at vanderbilt.edu
Sun Dec 19 02:24:16 CET 2004

Henric Nilsson wrote:
> Frank E Harrell Jr said the following on 2004-12-18 15:03:
>> That is not clear.
> Perhaps. And I think this is the issue. From the clients' perspective, 
> not a single FDA document states that you can use other software than 
> SAS. They haven't really thought about the fact that there isn't any FDA 
> documents encouraging the use of SAS for statistical analyses.

Right.  This reminds me of the worst movie of all time, Plan 9 From 
Outer Space, in which the psychic Creskin closes the movie by saying 
"Can you prove that this DIDN'T happen?".

> I don't think that the real problem is convincing regulatory authorities 
> that R (or any other (open-source) software for that matter) is 
> operating adequately. But clients and auditors seems to reason along the 
> lines of "rather being safe than sorry" and "nobody's ever been critized 
> for using SAS". From their perspective, when we propose using `some 
> other' software they start thinking that it perhaps may jeopardize their 
> trial results (and, all to often, "but doesn't FDA require SAS?").

Yes that is the hurdle.

> How to fight this? I don't know. Right now I'm thinking, "If you can 
> beat 'em, join 'em" and that the way of proving that `some other' 
> software works is through having similar documents and tools as the 
> commercial vendors.

With the job market for statisticians being excellent, I've often 
wondered why clinical statisticians in industry are so often timid. 
Statisticians need to show strength and stamina, along with good 
teaching skills, on this issue.

>>  And since FDA allows submissions using Excel, with not even an audit 
>> trail, and with known major statistical computing errors in Excel, I 
>> am fairly certain that it is not applicable or at the least is not 
>> enforced  in any meaningful way.
> The general preconception seems to be that neither SAS nor Excel needs 
> validation. E.g. the British guideline referenced in my previous email 
> states on p. 12 that
> "It is generally considered that there is no requirement for validation 
> of commercial hardware and established operating systems or for packages 
> such as the SAS system, Oracle and MS Excel, as entities in their own 
> right. However, most are configurable systems and so need adequate 
> control of installation and their configuration parameters."

This makes me wonder about the British system.  Have they not seen the 
serious calculation errors documented to be in Excel?

> Luckily for Excel, not a single word about precision and adequacy...

Right.  Thanks for your note Henric -Frank

> Henric

Frank E Harrell Jr   Professor and Chair           School of Medicine
                      Department of Biostatistics   Vanderbilt University

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