Re: RE: Input for survey about random sampling -number of pages

Just to qualify Eric's statement about the typical number of pages chosen for a BITV-Test, 3 pages is rarely sufficient. The number is mostly between 4 - 7, sometimes more. This page sample also includes described states (error handling, fold-out sections, layers and lightboxes etc) so if these would count as separate pages, the number would be higher.

BITV-Test  does not use random page sampling at the time being.

My regrets for today's telecon, I am still on holidays.
--
Detlev Fischer
testkreis c/o feld.wald.wiese
Thedestr. 2, 22767 Hamburg

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----- Original Message -----
From: evelleman@bartimeus.nl
To: v.conway@ecu.edu.au, public-wai-evaltf@w3.org
Date: 11.10.2012 08:48:15
Subject: RE: Input for survey about random sampling


> Hi Vivienne,
> 
> Maybe we should also add a question about how people conclude the number of pages of a website.
> Personally I would be interested to know the exact number of pages people use. For the BITVtest in Germany it seems to be 3 - 5 pages, for other testing schemes it is mostly not more than 30 - 50 pages. If we would take 20 percent of a website of 1.000.000 pages, that would mean checking many pages. In our discussion, there seems to be a tendency towards less pages.
> 
> This is also something to discuss in the Telco when we talk about confidence. How many pages do you need to have a certain amount of confidence in the results.
> 
> Kindest regards,
> 
> Eric 
> 
> =========================
> Eric Velleman
> Technisch directeur
> Stichting Accessibility
> Universiteit Twente
> 
> Tel: +31 (0)30 - 2398270
> 
> Christiaan Krammlaan 2
> 3571 AX Utrecht
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> 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: Vivienne CONWAY [v.conway@ecu.edu.au]
> Verzonden: donderdag 11 oktober 2012 5:02
> Aan: Velleman, Eric; public-wai-evaltf@w3.org
> Onderwerp: RE: Input for survey about random sampling
> 
> HI all
> I think question 12 should reflect a percentage of pages rather than a finite number.  In one of the discussions with the WCAG group they mentioned that 25% of the total pages sampled should be randomly chosen.  Can we re-phrase this question to include percentages?
> 
> 
> Regards
> 
> Vivienne L. Conway, B.IT(Hons), MACS CT, AALIA(cs)
> 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, 11 October 2012 5:18 AM
> To: public-wai-evaltf@w3.org
> Subject: RE: Input for survey about random sampling
> 
> Dear EvalTF,
> 
> Following our discussion last telco, the minutes of that meeting and some remarks sent to me, this is an update of the survey. Please send your comments to the list. Before we start making this a scientific research project, please keep in mind that this is input information for a first draft text to add a random sample.
> 
> ** Concept survey questions about sampling **
> 
> Note: You could fill in the survey more than once using different choices in the first question. Please note that the Methodology is about full websites (as defined in the Public Working Draft).
> 
> #01. Please choose the situation below for which you fill in this survey.
> Your evaluation activity is:
>  - (checkbox) In-house website evaluation for your own organization
>  - (checkbox) Website evaluation for external evaluation commissioner
>  - (checkbox) A re-evaluation of a website that you have evaluated less than 1 month ago
>  - (checkbox) In depth evaluation
>  - (checkbox) Basic evaluation
>  - (checkbox) Detailed evaluation
>  - (checkbox) Other - please specify below (text)
> 
> Please fill in the questions depending on the evaluation activity you have chosen in question #01:
> 
> #02. For which purposes do you evaluate websites:
>  - (checkbox) Provide in-depth analyses to guide website owners
>  - (checkbox) Monitor the accessibility of a website over time
>  - (checkbox) Final check before releasing or purchasing a website
>  - (checkbox) Provide label or other certificate of conformance
>  - (checkbox) Do large-scale evaluation of many websites
>  - [checkbox] Pre-sales activities (evaluating websites in order to initiate a contract)
>  - [checkbox] Evaluate websites in early/medium development stages
>  - [checkbox] Deliver training about Web accessibility evaluation
>  - (checkbox) Other - please specify below (text)
> 
> #03. Do you consult with the evaluation commissioner regarding the sample selection?
>  -(radio) Always
>  -(radio) Sometimes
>  -(radio) Never
>  -(radio) Depend upon whether the website is being done without their knowledge
> 
> #04. To what extent do the wishes of the evaluation commissioner influence the evaluation sample? 1= no influence (evaluator is independent in choice of evaluation sample), 5=total influence (evaluator is not independent in choice of of evaluation sample)
>  -(radio) 1
>  -(radio) 2
>  -(radio) 3
>  -(radio) 4
>  -(radio) 5
> 
> #05. Do you select sample pages for evaluation based on:
>  - (radio) Structured sampling only
>  - (radio) Random sampling only
>  - (radio) Automated sampling only
>  - (radio) Both structured and random sampling
>  - (radio) Both structured and random sampling supported by automated sampling
> 
> #06. Please specify any tools you use to help you select the sample, and how you use these tools for sampling. (text)
> 
> #07. If you use automated sampling only, how do you check the tool? (text)
> 
> #08. If you use structured sampling, how do you select the individual web pages? (text)
> 
> #09. If you use random sampling, how do you select the individual web pages? (text)
> 
> #10. How does re-evaluation of a website influence the sample? (text)
> 
> #11. Please specify if you sample pages differently or in different amounts for Basic Reporting, Detailed Reporting or In-Depth Analysis evaluation (text).
> 
> #12. What is the amount of pages you use in your sample when evaluating a website?
>  - (radio) 1 - 5
>  - (radio) 6 - 15
>  - (radio) 16 - 30
>  - (radio) 31 - 50
>  - (radio) 51 - 100
> 
> #13. If the amount of pages in your evaluation sample is variable, what are –in most cases – the factor(s) that have the most influence on the size of the sample:
>  - [checkbox] Size of the website
>  - [checkbox] Number of technologies on the website
>  - [checkbox] Amount of money available for the evaluation
>  - [checkbox] Number of templates
>  - [checkbox] Other, please specify below (text)
> 
> #14. How does the size of the website influence your selection? (text)
> 
> #15. How do you adjust your sampling approach for websites that are heavily template-driven? (text)
> 
> #16. If you use automated testing tool(s), does that change your sampling methodology?
>  - (radio) Yes
>  - (radio) No
>  - Please explain (text)
> 
> #17. How do you adjust your sampling approach for web applications? (text)
> 
> #18. How do you sample mobile applications? (text)
> 
> #19. Do you look out for widgets, snippets, and other web page components to avoid re-evaluating them every time they appear on a website?
>  - (radio) Yes
>  - (radio) No
> If Yes, how do you include them and the pages that they are integrated into the sample? (text)
> 
> #20. How do you identify and sample the functionality (processes) provided on a website? (text)
> 
> #21. Do you select further sample pages based upon results from an initial selection (eg. to balance web page types or success criteria)? (text)
> 
> #22. Please feel free to provide further thoughts or comments about how you approach sampling. (text)
> 
> Kindest regards,
> 
> Eric
> 
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Received on Thursday, 11 October 2012 11:04:36 UTC