[R] SAS or R software

[Shawn Way]

I've seen multiple comments about MS Excel's precision and accuracy.
Can you please point me in the right direction in locating information
about these?

Thank you very much,

Shawn Way, PE
Engineering Manager
Tanox, Inc.

-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Frank E Harrell
Jr
Sent: Saturday, December 18, 2004 7:24 PM
To: Henric Nilsson
Cc: R-Help; Douglas Bates; MSchwartz at medanalytics.com; Alexander C
Cambon; Jim Garrett
Subject: Re: [R] SAS or R software


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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