Measurement Primer

Measurement is hot—arguably the most controversial topic in the online industry. Everyone wants to know the secret to reaching a target audience online in the most efficient and effective manner, but since the medium is so young, there’s not much data to base decisions on. For decades, firms like Nielsen, Arbitron, MRI and others have been researching consumer interactions with traditional media to give advertisers a better idea of where, when and how to run their ads for best results. Online is no different. So let’s take a closer look at two of the leading online audience measurement firms—Nielsen//NetRatings and Media Metrix (soon to be officially called Jupiter Media Metrix)—in hopes of figuring out how these two fierce competitors do what they do and why we should trust them. Keep in mind that these firms measure online user behavior—not website performance. That’s the job of auditors like ABC and BPA International.

First the similarities: Both Nielsen//NetRatings and Media Metrix earn their daily bread by tracking (anonymously, of course) Internet user activity (both consumer and advertiser). Both have assembled fairly large panels of members “under voluntary surveillance,” have installed tracking devices in tens of thousands of computers worldwide and possess incredible amounts of data about online user behavior. They can tell you where Internet users go (which sites get the most traffic in a given time period), how long they stay there, which ads they see and click on and other stats like unique visitors, reach, average usage days per user, average unique pages per user per day and month, average minutes spent per person per page, per day, per week, per month and numerous other pieces of data that you probably didn’t even know you could use. For example, last January, Americans spent 57.5 billion minutes online, according to Media Metrix.

Media Metrix

Media Metrix was the first company to measure the Internet (as well as other digital equipment) beginning in January 1996. In October 1998 Media Metrix merged with its then biggest rival—Relevant Knowledge.

Today, they use a sample size of more than 100,000 individuals worldwide (recruited through a process called random digit dialing) to project audience usage of the Internet as well as all digital media. The samples report online usage at home and at work, including usage of both PC and Macintosh platforms.

Online behavior is measured by installing the patented Media Metrix Meter on the computers of sample members, enabling passive monitoring of all user activity both online and offline — click by click. This allows Media Metrix to measure real-time usage by individuals of the web and proprietary online services such as AOL, as well as patterns of software and hardware ownership and usage. All individuals are identified by the meter through their unique user ID’s, so a computer used by three people in a household will differentiate the experiences of each of those three people.

Measuring Internet usage at work is critical for many reasons. First, a huge amount of online usage occurs in the workplace. Second, usage patterns at work are different from usage patterns at home due both to the faster Internet connection speeds in the workplace and to work-related Internet activities. Moreover, many online marketers and advertisers are interested in targeting specific at-work audiences.

While at-work users are critical, this audience is more challenging to measure than users at home, according to Media Metrix. Based on several years of experience, they devised a rigorous at-work measurement methodology where the overall sample is operated as a single panel. Each respondent is expected to install the Meter on all the PCs he uses, whether those PCs are at home or at work. Separate audience projections are developed for each location. A third estimate is also created for those people who use their PCs both at home and at work. These three estimates, when combined, are used to measure the unduplicated audience estimates for each site, across locations. Should a new person join the household, that person simply has to add himself or herself to the Meter. This is a self-administered process, where the user fills out a short online form that captures the user’s age, sex and education.


At present, the biggest competitor of Media Metrix is Nielsen//NetRatings, spawned by Nielsen Media Research (a familiar name in this industry), ACNielsen and NetRatings, Inc.

The Nielsen//NetRatings service has built their panel (also via random digit dialing) from 8,000 in March 1999 to more than 110,000 members, under real-time measurement worldwide, in a 15-month span. Today, Nielsen//NetRatings collects real-time data from more than 65,000 panel members in the United States. The U.S. panel sample consists of 57,000 at-home users and 8,000 at-work users.

Nielsen uses a real-time methodology only to measure its Internet sample. Software is installed in the respondent’s computer that measures all “datastream” from the PC’s operating platform(s). All “real-time” data including Web usage is sent to Nielsen//NetRatings around the clock.

After agreeing to be monitored, Nielsen//NetRatings contacts the respondents every two months to determine if there are any pertinent changes in the households. Nielsen//NetRatings also re-contacts households that were originally selected but declared ineligible every six months. They are invited to join the sample if they have acquired a PC and have the capability to go online.

Additionally, the recently added My NielsenNetRatings information delivery system provides users with a custom-tailored, online view of data and analysis specific to a company’s needs, streamlining the process of viewing Nielsen//NetRatings data and reports.

With these two companies currently measuring the Internet, service, research techniques and pricing should be competitive in the years ahead and they will undoubtedly supply us with more numbers than we can handle. Of course, the industry’s lack of standardization in using the data available has undergone some criticism, but that’s a separate issue.