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RE: Sampling

From: Velleman, Eric <evelleman@bartimeus.nl>
Date: Sun, 18 Dec 2011 13:04:41 +0000
To: RichardWarren <richard.warren@userite.com>, Vivienne CONWAY<v.conway@ecu.edu.au>, Eval TF <public-wai-evaltf@w3.org>
Message-ID: <3D063CE533923349B1B52F26312B0A46732FF7@s107ma.bart.local>
Hi Richard, Vivienne,

Yes, agree that we would need the combination of the three samples to get to a good sample of the total website (within the scope) that is being evaluated. So the sample would include 1), 2) and 3). This way we would cover core resource, complete processes and random pages.
Kindest regards,

Eric

=========================
Eric Velleman
Technisch directeur
Stichting Accessibility
Universiteit Twente

Oudenoord 325,
3513EP Utrecht (The Netherlands);
Tel: +31 (0)30 - 2398270
www.accessibility.nl / www.wabcluster.org / www.econformance.eu /
www.game-accessibility.com/ www.eaccessplus.eu

Lees onze disclaimer: www.accessibility.nl/algemeen/disclaimer
Accessibility is Member van het W3C
=========================

________________________________________
Van: RichardWarren [richard.warren@userite.com]
Verzonden: zaterdag 17 december 2011 20:45
Aan: Vivienne CONWAY; Eval TF
Onderwerp: Re: Sampling

Hi Vivienne,

Random sampling is used to support/extend the other sampling processes. I
suggested using a combination of three types Structural, Task and Random.

The random sample is only one part of the sampling process, my suggestion
was to use it at the end. I am afraid that I did not structure my original
message well, I should have described random sampling at the end of the
list - not the beginning.

To be effective I believe that it is necessary to conduct all three sample
methods.

Richard

-----Original Message-----
From: Vivienne CONWAY
Sent: Thursday, December 15, 2011 2:40 PM
To: Velleman, Eric ; RichardWarren ; Eval TF
Subject: RE: Sampling

HI all

Unless I'm missing something, if we are talking about random sampling
methods, how do we make sure they include those 'complete processes'.  Do we
look at doing random sampling, plus complete processes, plus core elements
of the website (website purpose).?


Regards

Vivienne L. Conway, B.IT(Hons)
PhD Candidate & Sessional Lecturer, Edith Cowan University, Perth, W.A.
Director, Web Key IT Pty Ltd.
v.conway@ecu.edu.au
v.conway@webkeyit.com
Mob: 0415 383 673

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________________________________________
From: Velleman, Eric [evelleman@bartimeus.nl]
Sent: Thursday, 15 December 2011 7:35 PM
To: RichardWarren; Eval TF
Subject: RE: Sampling

Hi,

Yes, agree, the evaluation will need to specify the resources that have been
evaluated.

If the evaluation needs to be replicable and allow synchronous or
asynchronous comparisons (like monitoring) the evaluation sample must be
generated by a uniform random procedure that is partly described by Richard
in an earlier mail (see bottom of this message). Partly, because the
situation for our uniform random procedure is a bit more complicated than
with WCAG 1.0. There are some additional factors at work here that are
described in the Scope section like accessibility support and use of
different technologies and more. This is covered in WCAG 2.0 like also
described by Alistair in an earlier mail but we will have to check if that
is enough for the purpose of the evaluation report.

Question: Can we make a list of what should minimally be in the core
resource list (if available in the scope of the Website that is being
evaluated)? We will discuss the size of the sample later.

Using Richards list I come to:

Home Page,
Site Map,
Section landing pages (is there a maximum?)
Any sub-section landing pages (usually linked to from the section landing
pages)
Forms
Data tables
Multimedia (maybe we have to be more specific here)

While reading, the following additions seem interesting to add:
Help resource
Contact information resource
Search and extended search resources including resulting resources
Distinct web technology pages (...)
Pages with other programming languages
CSS alternatives for mobile, (more..)
Frames (are they still used?)

Also:
Resources representative of each category of resources having a
substantially distinct “look and feel” (typically representative of distinct
underlying site “templates”) (if identifiable).
Resources describing accessibility features and / or the accessibility
policy of the site (if any).


The resource list as a whole should, as far as possible, collectively
address all the applicable sampling objectives within the scope of the
evaluation.

Kindest regards,

Eric




________________________________________
Van: RichardWarren [richard.warren@userite.com]
Verzonden: donderdag 15 december 2011 11:09
Aan: Eval TF
Onderwerp: Re: Sampling

Hi
Eric is correct that we are evaluating (and therefore sampling) at a moment
in time.

I presume that we will include documentation of pages visited etc. so that
the process can be audited (we normally keep a checked list from the site
map). This check list can be just as useful for Vivienne's monitoring.

Richard

-----Original Message-----
From: Vivienne CONWAY
Sent: Thursday, December 15, 2011 2:11 AM
To: Velleman, Eric ; Boland Jr, Frederick E. ; RichardWarren ; Eval TF
Subject: RE: Sampling

Hi all

For my current research project, I have used a targetted sampling method.
As well as scanning the whole site with automated tools to check for trends,
I have chosen 5 pages from each website to check manually according to the
WCAG 2.0 guidelines.  These pages reflect as many WCAG 2.0 checkpoints as
possible: home page, contact us page (or something with a form), page with
photos, page with multimedia, and a page describing their services or other
page with some complexity.

As I check these websites repeatedly, I will check the same pages to see
their progression (or degeneration) over time.


Regards

Vivienne L. Conway, B.IT(Hons)
PhD Candidate & Sessional Lecturer, Edith Cowan University, Perth, W.A.
Director, Web Key IT Pty Ltd.
v.conway@ecu.edu.au
v.conway@webkeyit.com
Mob: 0415 383 673

This email is confidential and intended only for the use of the individual
or entity named above. If you are not the intended recipient, you are
notified that any dissemination, distribution or copying of this email is
strictly prohibited. If you have received this email in error, please notify
me immediately by return email or telephone and destroy the original
message.
________________________________________
From: Velleman, Eric [evelleman@bartimeus.nl]
Sent: Thursday, 15 December 2011 7:22 AM
To: Boland Jr, Frederick E.; RichardWarren; Eval TF
Subject: RE: Sampling

Frederick,

your remark made me think of time lapse sampling:

It could be that a website/webpage changes over time on purpose. For
example: it could show images and text related to the time of the day or the
feeling of the owner. If the owner feels bad at 8 am, then the page is dark
but after his first cup of coffee, the page looks bright and happy...
In that case it could be interesting to sample the same page at different
times but I do not know how to put this into the methodology, maybe in a
footnote?

Eric

________________________________
Van: Boland Jr, Frederick E. [frederick.boland@nist.gov]
Verzonden: woensdag 14 december 2011 21:48
Aan: RichardWarren; Eval TF
Onderwerp: RE: Sampling

We may also need to sample over time, since a site’s pages/content may
change over time, which could affect WCAG2.0 conformance and/or resultant
accessibility of the site.. or provide a date/time (required component) of
evaluation for pages/site..  Questions that may arise in this regard are:
how often to sample, etc. (for example,  do we just want to sample when
there are major content changes, or do we just want to sample at regular
intervals regardless of any perceived changes, or do we want to apply
different strategies for different parts of a site?)

Thanks Tim Boland

From: RichardWarren [mailto:richard.warren@userite.com]
Sent: Wednesday, December 14, 2011 2:32 PM
To: Eval TF
Subject: Sampling

Hi,

To reduce the effort of evaluating a large site I suggest that there are
three methods of sampling the site’s pages/content which can be coupled with
a barrier identification technique to avoid constant repetition.

The three sampling techniques for manual evaluation are  :-

1) Random sampling  - selecting a number of pages at random. This can be
done by making a random selection from the site map, or to take every tenth
(or other suitable number) of links from the site map.

2) Structure sampling – selecting the higher level structural pages such as
Home Page, Site Map, section landing pages (usually linked from the Home
page within the main navigation bar), any sub-section landing pages (usually
linked to from the section landing pages, plus (if not already found) a
sample of pages containing elements such as forms, data tables and
multi-media.

3) Task orientated sampling – Completing the key tasks on the site required
to meet the site’s purpose. This might include tasks such as to source
certain information, place an order or participate in a discussion.

Barrier identification reduces effort further by noting examples of common
failures in technique employed within the site and once identified and
commented on we can ignore further occurrences within that section.

We use a combination of all three sampling methods. We start with 2
(structured sample) to explore the site and obtain an overview of its’
purpose etc. Next we attempt the key tasks.  Then we do a random sample
(skipping any pages already sampled).

Richard

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not disclose or use the information contained within. If you have received
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Received on Sunday, 18 December 2011 13:11:48 GMT

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