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The following message was posted to: PharmPK
What is it we should validate?
I have been using these spreadsheets since years, I know that they
work, why should I start to validate?
Should we test standard Excel functions?
Standard Excel does not have part11 compliant audit trail, what to do?
Everybody can easily access Excel applications, how to ensure data
security and integrity?
How to prevent that somebody changes the Excel spreadsheet?
please provise mail ID who do Excel validation
thx
ashish saxena
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The following message was posted to: PharmPK
Ashish, depending upon which functions you use, your Excel spreadsheets may "work" but the results might be inaccurate. There have been known flaws in Excel statistical functions since the early versions and these have been faithfully maintained for backward compatibility.
Have a look for
Knusel, L. "On the Reliability of Microsoft Excel XP for Statistical Purposes"
McCullough, B.D. & Wilson, W. "On the accuracy of statistical procedures in Microsoft Excel 2003" Comp. Stat. Data Anal.
Pottel, H. "Statistical flaws in Excel"
However, the criticism is against the algorithms used, not against lack of consistency.
All the very best,
Bernard
Bernard Murray, Ph.D.
Senior Research Scientist, Drug Metabolism
Gilead Sciences, Foster City CA
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Ashish and Bernard:
The question here is more braoder, do we need to validate standard age old known software? My opinion is yes!!
In my opinion Validation is nothing but documenting that the intended tool (software or spread sheet etc.) serves the purpose on hand. If your intention is to use Excel (I like this very much) for prolonged time for similar excercise like PK calculations, or plotting etc. You have to customize (number of decimal points for calculation, display and reporting), introduce history sheet (there is a way you can creat a history sheet), use password protection for accessing and alterin the data fields. Once you create this basic shell in your excel save it as a designated file or macro.
Once you save this excel file take a known dataset run your tests in your excel spread sheet and compare it against the standard software (such as SAS or WinNonLin) create a validation report and save it for future use.
For more details, look on the internet for a presentation or workshop content on "how to make Excel as 21 CFR Part 11 compliant"
If I had this problem on my table these were my approaches but there may be better alternatives and I would like to hear about the alternatives. Hope this suggestion helps. Prasad Tata, Ph.D., FCP
St. Louis, MO 63146
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No. The excel fomula and sheet(s) can be validated and the sheets locked down such that only certain fields may be accessible to the user. The weakness is in that the author may change the contents of all cells without those changes being captured via an audit trail.
--
There are also software companies that provide "cloaks" which supply auditing mechanisms for excel and similar software. Of course the excel as well as the cloak need to be validated. Here are three there are numerous others.
http://www.part11solutions.com/
http://www.ofnisystems.com/
-- Edward F. O'Connor
78 Marbern Drive
Suffield, Ct 06078-1533
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