[Year 12 SofDev] usability - NF requirement or constraint or both???

[Mark]

Hi Katherine.

I can see 'usability' being listed as an NFR in the sense that: 'The
finished solution must be usable.'
It could also appear as a constraint on design choices for the same reason:
'The solution must be designed in a way that makes it very usable for the
end-user.'

Much of a muchness. There is some natural overlap in theory concepts.

For example, I still can't work out how scope is different to defining all
FR and NFR.
If you have defined ALL requirements, is the scope not *also* defined?
Anything that does not appear as a requirement must be - by definition -
not in scope.

Otherwise, listing things that are not in scope could go on til the crack
of doom.

e.g.

Solution: A toaster

In Scope:
- Scorch bread.
- Scorch muffins.
- Scorch crumpets.

Not in scope:
- Train elephants.
- Predict hurricanes.
- Solve crosswords.
- Blend mangoes.
- Pat the cat.
- Take the wife out dancing.
etc

Can anyone give an example of how something that is *not* a requirement
still *could* be in scope?

Regards
Mark



On 6 December 2015 at 08:59, Young, Katherine A <
young.katherine.a at edumail.vic.gov.au> wrote:

> Hi all,
>
> I’ve attached a graphic organizer that will hopefully get my kids thinking
> more carefully during their analysis of a problem, need or opportunity. Do
> others use something similar? I’d love to hear your feedback.
>
> However, in doing so I realized that usability is listed as both a
> non-functional requirement AND a constraint. My brain had been thinking
> that a social constraint such the users’ level of expertise or some other
> "audience characteristic" would impose a non-functional requirement in
> relation to the usability of a solution.
>
> Could someone please explain the difference between usability as a
> constraint and as a NF requirement? I know that I WILL be asked the same
> question :-/
>
> Thank you!
>
>
>
>
> Regards,
>
>
>
> *Katherine Young*
> 11C Mentor
> Mathematics & Information Technology Teacher
>
> *Castlemaine Secondary College*
> *Etty Street Campus*
> Etty Street
> Castlemaine VIC 3450
> T: (03) 5479 4222   |  F: (03) 5479 4230
>
>
>
-- 

Mark Kelly

mark at vceit.com
http://vceit.com
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