A Look at Panel-Based and Server-Based Online Audience Measurements and the Role of Third-Party Auditing
A Point of View By Bill Perry, Director, Special Project, Audit Bureau of Circulations, Schaumburg, Ill.
Part one in a three-part series.
The Internet is arguably the most measurable media in history. Numerous options
abound for online publishers seeking to measure the health and viability of their
Web sites. Not surprisingly, the wealth of choices also causes a lot of confusion about the
underlying differences between the many forms of measurement.
This article is the first in a series of three intended to address the confusion surrounding
the different online measurement options, the methods that each measurement
company uses to determine unique users and page views, and the future of Web site
measurement methods and metrics.
In this article, we’ll focus solely on the two primary methods used to measure a Web
site’s audience and the role of third-party auditing in providing independent verification
for either method.
Panel-Based Audience Measurement
The most recognized online panel-based audience measurement companies are
Nielsen//NetRatings and comScore Inc. These companies gather a sample panel of
Internet users and track each user’s specific Internet usage habits. Typically, this includes
installing a piece of software on the panelist’s computer that tracks their activity when
they are online. These companies then project the usage and habits of the entire U.S., or
Canadian, Internet population based on the data gathered from its panelists. The size and
diversity of the panel are essential to projecting statistically accurate numbers.
Server-Based Audience Measurement
There are numerous Web site analytics firms that provide useful measurements direct
from a site’s server or pages served from a Web site. Some of the recognized names in this
area are companies like Omniture, Google Analytics, Visual Sciences and WebTrends.
These companies track your Web site’s traffic activity using two common methods. The
first method involves installing a Java script tag on the pages of your Web site. The code
is programmed to send the traffic activity data back to the Web site analytics firm. The
analytics firm then takes that data and produces a report for you. The second method
allows you to upload the log files from your Web site to a software program that also
produces a summary report.
The server-based measurement method tracks almost 100 percent of the traffic
activity on your Web site, and may include some misleading activity such as internal
traffic, duplication and spiders and robots. While you can set up filters to remove some
misleading activity, this requires constant maintenance and updating since new spiders
and robots are created frequently.
Web sites using server-based measurements may also experience inflated traffic data due
to user cookie deletion. Cookies are small text files stored on the user’s computer that
collect a variety of data that identifies the user. Some users delete cookies from their
computers or reject cookies as part of their Web browser settings. What does this mean?
Since cookies identify unique users, cookie deletion can cause the same PC user to be
counted as multiple visitors therefore inflating the Web site’s overall traffic activity. Cookie
deletion inflation may be offset by users that reject cookies or multiple users accessing the
same computer.
These are some advantages and disadvantages to both forms of audience measurement:
| PROS | CONS |
| Panel-Based Measurement |
- Panel participants can also supply detailed demographic data.
- Panels may be better suited to eliminate duplicative traffic (home and work).
- Used by most large national advertisers/agencies, primarily for demographics.
- Good option for measuring large sites with national audiences.
|
- Size and diversity of panel are imperative for accurate numbers.
- Data may be volatile from month to month, due to the number of panelists in the survey.
- Potentially limited at-work activity.
- May not adequately measure smaller or geographically narrow sites or sites with significant foreign-based traffic.
- May not track traffic from many new mobile devices.
|
| Server-Based Measurement |
- Tracks nearly 100 percent of the actual Web site activity recorded at the server level, including work-based, military, and foreign traffic as well as mobile devices.
- Log files are able to provide detailed user behavioral actions such as top pages, sections and user pathing through your site.
- Good option for sites not covered by panels.
- Ad delivery and measurement are also server-based.
|
- User cookie deletion can inflate overall traffic numbers.
- New spiders and robots can create misleading activity if not properly filtered.
- One user accessing the Internet from multiple computers may create duplication.
- Does not provide audience demographics.
|
The Role of Auditing Companies
You may have read about the Interactive Advertising Bureau’s call for Nielsen//NetRatings and
comScore to undergo MRC accreditation. This type of accreditation audits companies’ underlying software
or methodology used to generate the data, but not audit or report data that is specific to a selected period of
time.
ABC is working with the panel-based audience measurement companies—Nielsen//NetRatings and
comScore—to develop an audit program to verify specific key statistics generated by panels for inclusion in
the new U.S. daily newspaper Audience-FAX reporting initiative.
For publisher’s using server-based audience measurement, ABC already
offers an audit to verify the data produced by the log files. A Web site’s server, or
your analytics company, maintains a complete record of all activity that occurs
on the site. These records are called log files and are rich with data about your
site’s traffic such as the number of unique users, page views, top requested pages
and more. During an ABCi traffic audit, auditors conduct specific tests designed
to detect and remove misleading activity from your log files, including nonhuman
generated activity, internal activity and spiders and robots. The final
output of the audit is a verified report that accurately portrays your Web site’s
total traffic activity.
Recordkeeping vs. Verified Data
To better understand the difference between the report produced for you by
an analytics firm, such as Omniture, and a report produced as the result of an
ABCi traffic audit, I’d like to share an analogy with you. This will be especially
helpful to those of you familiar with the periodical publishing industry.
Every year publishers undergo an audit that verifies their circulation by
distribution channel and ensures that it is compliant with industry standards.
Throughout the year, they maintain a variety of circulation records that are
needed to conduct and support the audit. These circulation records are just like a
Web site’s log files. Some ABC periodical members choose to have their circulation
records maintained by a fulfillment company such as Palm Coast Data or
Kable. Think of these fulfillment houses as a Web site analytics firm. The
analytics firm may do a great job of maintaining records and providing neat
summary reports, but it doesn’t verify that the traffic complies with industrystandard
guidelines and is properly recorded—just like a fulfillment house does not
guarantee the quality of a magazine’s circulation practices. That’s where an
independent third-party audit plays an important role—examining and substantiating
the accuracy of a Web site’s traffic claims and ensuring it meets industry
standards.
Next in the Series
I’m sure your next question is, “How can a Web site’s numbers vary so widely
depending on the measurement company?” In the next article in this series, I will
examine how each of these types of Web site traffic measurement companies can
generate a different number for two of the most common metrics—unique users
and page views.
For More Information
ABC can help you better understand the key trends and issues in
online auditing. For more information on ABC’s interactive audit
services, members are encouraged to fill out an online request form
or contact ABC’s
manager, marketing and sales, at
(720) 324-0558.
About ABC
With more than 4,000 members in North
America, ABC is a forum of the world’s
leading magazine and newspaper publishers,
advertisers and advertising agencies.
The organization provides credible, verified
information essential to the media buying
and selling process. ABC maintains the
world’s foremost electronic database of
audited-circulation information and an
array of verified readership, subscriber
demographics and online activity data.
To learn more, visit
http://www.accessabc.com.
Bill Perry
joined ABC in
1985 as a
newspaper field
auditor. He
joined ABC
Interactive
(ABCi) in 1997
as manager of
interactive
auditing and was
promoted to
director, special projects in 2000. Perry’s
current responsibilities include leading a
team of auditors in a variety of non-traditional
auditing projects including Web
activity, insert verification and centralized
audits. He has twice received ABC’s prestigious
Deneen Award for staff members that
have gone above and beyond the call of duty.
Perry earned his bachelor of science degree
in accounting from Indiana University.
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