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Re: LC-67 leftover -- MUST use MUST?

From: Mark Skall <mark.skall@nist.gov>
Date: Wed, 25 Jun 2003 16:27:03 -0400
Message-Id: <>
To: Alex Rousskov <rousskov@measurement-factory.com>
Cc: Lofton Henderson <lofton@rockynet.com>, www-qa@w3.org

At 02:11 PM 6/25/2003 -0600, Alex Rousskov wrote:

>On Wed, 25 Jun 2003, Mark Skall wrote:
> > I still have heard no satisfactory reasons not to require the
> > keywords used (in caps).  They are an easy way to get the reader's
> > attention that a requirement is present.
>My understanding is that W3C considers UAAG an example where RFC 2119
>keywords are not good enough. See authors comments quoted by Lofton.
> >[5] http://lists.w3.org/Archives/Public/www-qa-wg/2003Jun/0039.html
>Also, please do not mix the question of whether to use RFC 2119
>keywords with a question whether keywords must be in caps. I disagree
>that specs MUST use RFC 2119 (I think they SHOULD). I agree that
>requirements MUST be programmatically identifiable (without AI

This is a useless requirement. Whether or not the requirements are 
identifiable is completely subjective and, (I might add) not testable.  We 
have some pretty good history that RFC 2119 makes requirements 
identifiable.  We need to use objective measures to ensure that 
requirements are identifiable, not subjective ones.

> > I don't buy "** Alt.2 or Alt.3 strongly encourage uniformity rather
> > than forcing it, and that should suffice.".  Why should that
> > suffice?  Encouraging, but not mandating, this MAY result in
> > non-compliance with specific requirements due to poor communication
> > (didn't know it was a requirement).  What can be gained by this?
>This is a strange argument. If we accept "didn't know it was a
>requirement" as an excuse, there is no reason to write SpecGL at all.
>SHOULD and MUST have about the same visibility and about the same
>probability of being unknown due to poor communication.

Huh?  We're talking about whether or not to mandate the keywords in RFC 
2119, not whether to use MUSTs vs. SHOULDs.  Not mandating the keywords may 
(will) result in specs using alternative language.  Any alternative 
language is permissible.  UAAG uses the imperative voice, but another spec 
may use a completely different set of keywords (have to, probably will, 
might, etc.)  Can we take the chance that their subjective interpretation 
that these new keywords make requirements identifiable result in other 
people thinking they're identifiable (again, a subjective decision)?  I 
think not.

Mark Skall
Chief, Software Diagnostics and Conformance Testing Division
Information Technology Laboratory
National Institute of Standards and Technology (NIST)
100 Bureau Drive, Stop 8970
Gaithersburg, MD 20899-8970

Voice: 301-975-3262
Fax:   301-590-9174
Email: skall@nist.gov
Received on Wednesday, 25 June 2003 16:27:29 UTC

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