Validation of R

On Thu, 17 Apr 2003 10:38:06 -0400

However, the perception out there is the "SAS is the accepted software" 
especially for regulatory submission and especially in the US. Thus, I 
think validation usually means "Yeah, but did you use SAS to get the 
answer" , no matter how irrelevant the question is. For a 
non-statistician, or a person doing validation certain software do not 
need validation (Microsoft Word, SAS etc.) certain other , perhaps more so 
for open source, validation is essential.

SAS is NOT the accepted software for FDA, because FDA does not accept ANY brand of software.  This is really a "mind share" issue at pharma companies.  SAS is not validated in every sense; there is a huge list of current SAS bugs.

Validation is best done on a per-project basis as you can't anticipate all aspects of a particular dataset.  The validation can be done by independent calculations of pivotal findings.  For R there is an especially good opportunity because if you are using the base packages you can run essentially the same code in S-Plus to get an independent validation of the underlying calculations (but not of your S code).  The base code in R is independent of that in S-Plus (this is not true of most add-on packages by users).  There is no other "SAS" you can run.

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Frank E Harrell Jr              Prof. of Biostatistics & Statistics
Div. of Biostatistics & Epidem. Dept. of Health Evaluation Sciences
U. Virginia School of Medicine  http://hesweb1.med.virginia.edu/biostat