A Metric for Every Reason

It is often overlooked that different metrics have different utility to different parties when ranking Web sites. Media planners, publishers, networks, and the press all have different perspectives on what type of engagement metric is best for their needs.

The truth is that different situations need different metrics. A metric useful for a media planner in an agency looking at display ad inventory may not be useful for a marketer who has just designed an interactive Web site. Let’s look at some metrics, both traditional and new Web 2.0 advertising metrics, and see where each may be most useful

Unique visitors is a measure of how many unique (i.e. different) individuals visit a site over some period of time. This is an appropriate metric to quantify the size of the unduplicated audience a site reaches. Combining the unique visitor metric with the frequency of visits, you have a measure of both reach and loyalty.

Time spent comes into play when you want to compare the level of engagement between sites. This is especially true when looking at categories like social networking sites. The number of visits alone won’t help you measure the success of these sites in serving their customers. One site may be able to create environments where the level of duration for each visit is 10x the time spent per visit at another site. For other sites like search engines, the brevity of the visit is a virtue, so time spent is not a good measure of engagement; repeat usage might be better.

Page views, which are much less relevant in a Web 2.0 environment for sites using technologies such as AJAX, are still a helpful metric for many sites. Page views will likely be used as a measure of involvement for sites that maintain a traditional page definition.

For media planners and publishers, Comscore has introduced a new metric that evaluates sites based on their ability to serve advertising media -- the number of ad views. Ad views are the number of advertising impressions that will be seen by a visitor to that publisher Web site. Each site has a different ability to deliver ads to its visitors. Media planners can use ad views by publisher site to derive actual reach and frequency levels against specific target groups of visitors.

When you know how many ad views are being displayed to different demographic consumer segments, media buying decisions can be improved. Planners can easily compare sites based on their ability to deliver the number of ad impressions they would like to buy. Page views are insufficient because sites display a different number of ads per page, and in a Web 2.0 environment, it is possible that dozens of ads can be served to consumers without a new page being displayed.

Ad views can be combined with other metrics, such as visits, to understand whether a consumer visiting a site will be bombarded by dozens or just a few ads in a visit. A very large number of ad views per visit may mean unacceptable publisher clutter, where a message could be lost among those from dozens of other advertisers.

Having a wide array of different metrics available is a good thing -- one size does not fit all. The focus on just one metric may create a convenient ranking of Web sites, but advertising views and duration metrics provide valuable insight across publishers and can help drive significant improvements in media planning and buying.