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R: 2 or 3 levels: beware of the compromise effect

From: Roberto Castaldo <r.castaldo@iol.it>
Date: Fri, 26 Mar 2004 19:33:59 +0100
Message-ID: <40586537002E8434@ms002msg.mail.fw> (added by postmaster@ms002msg.fastwebnet.it)
To: "'Yvette P. Hoitink'" <y.p.hoitink@heritas.nl>, <w3c-wai-gl@w3.org>

Hi Yvette, Hi group,

I remembered a case study from when I was taking management studies classes
and looked it up again (thanks Google!). This study showed that people did
not want to choose the extreme option and were more likely to choose the
second option if they could choose between 3 instead of 2 options. McDonalds
has known this for quite a while: letting you choose between small, medium
and large means more people will choose medium than without the large
option. In literature, this is known as the 'compromise effect'.

This article explains this phenomenon in clear terms:
http://www.indicator.co.uk/books/uk101sbk/example1.htm. A more scientific
explanation can be found here:

In WCAG terms, the compromise effect means that more people will be aiming
for level 2 if they can choose between 3 levels than if they could only
choose between 2 levels. Thus, from a psychological point of view I would
argue against 2 levels instead of 3.

Roberto C:
And how would people behave with 2 levels? How will this compromise effect
work with only 2 levels avaliable? 

Will developers point to level 1 - "Ok, it's the core level, never mind the
other one" - or will be pushed to complete all criteria?

I simply don't know, but in this case the possible compromise does't seem to
be acceptalbe.

We all should do our best to guide people to apply all guidelines, but let's
check the worst case in both situations (2 or 3 levels):

- 2 levels: I think that many users could choose to apply only level one, so
IMHO this case is quite bad and we should try and avoid it.
- 3 levels: if many developers choose "medium" option, they will work on
each level 1 and level 2 criterion; it's not so bad, after all.

My best regards,

Roberto Castaldo
Coordinatore www.Webaccessibile.Org
IWA/HWG Member
Cell 348 3700161
Icq 178709294
Received on Friday, 26 March 2004 13:34:58 UTC

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