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Do we share an understanding of "requirement"?

From: Detlev Fischer <fischer@dias.de>
Date: Tue, 13 Sep 2011 09:35:02 +0200
Message-ID: <4E6F07A6.8030005@dias.de>
To: public-wai-evaltf@w3.org
Hi everyone,

I am getting quite concerned myself now, so please forgive me if I break 
my promise to “stay shtum” to kick off a discussion about we mean when 
we are using the term *requirement*.

1) Do we agree that we should not include requirements for
    attributes which we have not shown to be *feasible*?

2) Do we agree that a requirement identifies a *necessary* attribute,
    capability, characteristic, or quality of a system in order for
    it to have value and utility to a user?

3) Do we further agree that requirements should be *verifiable*, i.e.
    that tests can eventually prove that the thing built (our
    methodology, in this case) meets the requirements we have specified?

If we agree on these three points (and I hope we do) then R03: Unique 
interpretation and R04: Replicability should be first of all feasible; 
they should be shown to be necessary (e.g., the methodology would have 
reduced credibility without them); finally, they should also be 
verifiable (e.g. replicability and uniqueness of interpretation can be 
proven in independent tests of a real-world sites).

If you agree so far, were do we stand in this?

*Feasible:* I have not read a single statement on this mailing list so 
far that has offered any evidence that replicability and unique 
(unambiguous) interpretation are feasible  -  especially if the 
methodology stays on a fairly generic level (i.e., if it does not 
prescribe the tools to be used, a step-by-step procedure, and detailed 
instructions for evaluating test results).

*Verifiable:*  We do not know yet, we have not built anything so far 
that we could use to carry out tests independently and then compare 
results. So let’s move on to second-best, the various methods we 
currently use. I would ask all of you to report on any tests that were 
carried out by two independent testers and arrived at the same result. 
No one has come forward and claimed it has happened, or even, that it 
can be done.

*Necessary:*  Some of you may believe that replicability and uniqueness 
of interpretation are necessary because the methodology would be less 
credible without them. But unless the methodology mandates that tests 
are actually replicated, the claim of replicability is just a red 
herring. I think that any claims that cannot be verified in practical 
application seriously undermine the credibility of a methodology.

Detlev

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Detlev Fischer PhD
DIAS GmbH - Daten, Informationssysteme und Analysen im Sozialen
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Received on Tuesday, 13 September 2011 07:35:27 GMT

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