Sometimes this can be known, and other times it must be assigned via an
edit rule. It depends on the activity that truncates the duration. If
it was a user going elsewhere online (or even moving to a desktop
application, e.g. Excel), comScore can capture that. If the activity
that truncates duration is the user getting up and walking away from
the computer, that's when an edit rule is necessary.

----- Original Message -----
From: dhs1986@...
Date: Tuesday, July 17, 2007 3:22 pm
Subject: Re: [webanalytics] Re: Nielsen NetRatings Switch-Off to Time
on Site
To: webanalytics@yahoogroups.com

> Judah,
>
> For what it's worth, I'm pretty sure that (in contrast to
> javascript-based web analytics systems), the audience measurement
> services are able to capture visit duration for the last page
> visited on a site with their tracking software. I'd have to double-
> check with my client reps to confirm...
>
> David
>
> -------------- Original message --------------
> From: "Judah Phillips" <judahphillips@...>
> Hello Jim,
>
> Y'know I share the love and respect. I also hear ya loud and clear
> aboutthe differences in understanding the impact of a duration
> metric on "macro"
> and "micro" level site analysis. In fact, your past, genial posts
> aboutthis issue are quite thought provoking.
>
> Simply put Nielsen is providing a new metric for "measurement" not for
> "evaluation." Such categorization makes the announcement easier to
> accept.I get agitated in the evaluation of a site based on a time-
> metric *without
> context*.
>
> If I may briefly paraphrase the "macro"... what you are saying is
> that measures of "frequency" on the web are so noisy, that using
> "duration"as a proxy for "frequency" makes sense in that it is
> comparable across media
> types because it is inexact in similar ways. Therefore, because of
> historicprecedent, a time-basis for media buying becomes a de
> facto "standard" for
> approximating audience "weight" on the web. Thus, with a Total
> Time Online
> metric, a buyer of electronic media can apply existing models to
> purchase a
> known quantity of time (i.e weight) and predict a known result
> (i.e I buy X
> weight, I get Y sales).
>
> That makes sense to me if the theory holds true, but, darn, it is
> suboptimal, especially as a measure of Web 2.0 sites. It's not
> just single
> page visits that aren't counted, but the time spent on the last
> page in the
> session isn't counted either. If the majority of your "engagement"
> takesplace on the last page in the session, then the "total time"
> metric fails to
> account for that too. The time data is trimmed at the beginning
> and the
> end. Take for example Zillow. In my personal experience, I engage
> the last
> page I request, panning, zooming, checking my neighbors home
> values, then I
> leave. In the current model, my time on the last page is not captured.
>
> One could assume that rich internet applications and sites that serve
> RIA transfer more megabytes then "web 1.0" sites. Does that mean I
> shouldmeasure and rank on "megabytes transferred" as indicator of Web
> 2.0engagement? Is it a useful measure of "weight"? No, it's not, and
> I'm not
> sure "total time" is the solution either. That said, from the
> macro level
> and business model perspective, I get why Nielsen is moving in that
> direction. I also understand why they are backing off a bit on the
> importance of the metric for "evaluation" and talking about how
> they are
> still tracking page views and other metrics too.
>
> I'll still give Nielsen props for making people think
> about "the numbers" and using their influence to bring light to the
> challenges of new media measurement. At the end of the day though,
> it'sstill tough data to believe since I have no insight as to
> whether the panel
> suffers from coverage error and selection bias, regardless of the
> technicalchallenges to measuring time on the web.
>
> Judah
>
> [Non-text portions of this message have been removed]
>
>
>
>
> [Non-text portions of this message have been removed]
>
>