Hi Jared, How are you? It didn't seem you were alone in the "accusing" (your word;-)) camp.
I ALWAYS explain to clients that: - ET does not equal measuring "seeing" (because seeing is a cognitive action), it's the CORRELATION between "seeing" and point of regard fixations and saccades we're measuring. - ET measures foveal point of regard and NOT peripheral vision which is ALSO used by people to gather information about the stimulus whether it's a screen, a room or anything else, so yes, you can "see" things off fovea (whether they're actually there or not is another question;-)) - Calibration quality in ET is key if we are to reduce error margins to acceptable levels - error margins basically translate into a drifting of correspondances across the X and Y coords. We need to take this into account when defining Areas of Interest for analysis. - ET sampling rate is another - different machines have different rates, so yes there can be missed data. - Look out for how methodology can change behaviour (the "think aloud" vs "silent task" issue) - ET results should be addressed ONLY within the scope and context of the tasks that were given to the respondents, i.e. don't use results from one task to imply something else. - Usual caveats about sample sizes (qual vs quant) and statistical projection Where I'm finding ET really interesting is with larger sample sizes. We're looking right now at examples coming from the 100-person study about online surveys (a whole 'nother controversy;-)) we did earlier this year. What's interesting about that is we have ET data AND survey answers - which themselves infer that respondents "read" questions and "saw" labels because they selected items and input text answers too. Seeing how these line up - or not - is really providing some interesting learnings. Have a great day! Kate [email protected] +1 514 502-5862 ________________________________ From: Jared Spool <[email protected]> To: Kate Caldwell <[email protected]> Cc: [email protected] Sent: Friday, August 21, 2009 9:40:42 AM Subject: Re: [IxDA Discuss] Eye-Tracker software/hardware recommendations On Aug 20, 2009, at 9:43 AM, Kate Caldwell wrote: > I have an SMI system in our facility in downtown Montreal. > I'm very interested in the discussion. The pros and cons of using ET > for usability testing seem pretty well described above. > > At the same time, I dislike what I understood as the suggestion that > some practitioners are using ET to con clients. NO methodology or > tool should be offered (honestly) without being clear about its > deliverables, benefits and limitations. Kate, I agree. Given that I'm the one making the suggestion, (and I think it was more of an accusation than a suggestion,) I'd like to say that I also think that we need to be honest about what we do, especially to ourselves. I'd be interested in hearing the disclaimers you give your clients before presenting inferences from eye tracking data. Jared __________________________________________________________________ Be smarter than spam. See how smart SpamGuard is at giving junk email the boot with the All-new Yahoo! Mail. Click on Options in Mail and switch to New Mail today or register for free at http://mail.yahoo.ca ________________________________________________________________ Welcome to the Interaction Design Association (IxDA)! To post to this list ....... [email protected] Unsubscribe ................ http://www.ixda.org/unsubscribe List Guidelines ............ http://www.ixda.org/guidelines List Help .................. http://www.ixda.org/help
