Last week I was meeting with a client (Hi, Marlene!) when we started talking about the demographic composition of an entity's audience for Unique Visitors (UVs), as opposed to Page Views (PVs). As you can imagine, when you're chief research officer at Comscore, you go to a lot of meetings where clients want to talk about... how can I put this delicately... let's just say, when they love their numbers, they seldom call.
Sometimes when talking with clients, I hear the concern that their site targets a specific demographic niche, and yet that niche comprises a disappointingly small portion of their UVs. Invariably I'll hear something like this: "But 85% of our registered users are left-handed Irish backgammon players aged 45-54!" The implication being, the profile of their UVs skews somewhat less targeted.
But here's the thing. The UV metric is democratic to a fault. Every visitor -- the accidental tourist who hits the site once for thirty seconds ever, and the core user who spends an hour a day there -- counts once and only once in the UV. There are a lot of things that can affect a site's UV demographic composition; one of them is search. Suppose that essence.com, which targets African-Americans, runs an article about Tiger Woods. It is possible that many golf fans who do not happen to be African-Americans will end up at essence.com that month because they searched for "Tiger Woods." This search-generated traffic will contribute to the UV metric, even as it dilutes the demographic target.
A better gauge of a Web entity's user profile would be to look at the composition of PVs, because heavy users will drive PVs and tend to counteract the diluting impact on the core target that a UV metric can have. In December 2007, for example, MMX reported that 62% of Unique Visitors to aarp.org were age 50+ (eligibility for AARP kicking in at age 50); but 77% of their Page Views were accounted for by persons 50+, and 79% of their total minutes.
But there is another important reason to think in terms of pages when assessing a web entity's audience make-up. Ads are distributed across pages, not UVs. The more pages one consumes, the more ads one is exposed to, and the more likely that consumer is to see your ad. If an advertiser runs a campaign on a site, the audience profile of the exposures to that campaign will tend to mirror the profile of the Page Views, not the Unique Visitors. In the AARP example above, then, let's restate thusly: 62% of the aarp.com unique audience is comprised of persons 50+, but these persons see almost 80% of the ads.
With a behavioral targeting as opposed to demographic targeting construct, the difference can become even more pronounced. A specific automotive shopping site (here I've chosen to mask the property) had 4.2 million UVs in December 2007. 12% of these UVs (roughly 500,000) came from among the 5.3 million online users who were among the 20% heaviest visitors to automotive manufacturer websites in that month (and who are thus logically highly likely to be in-market for a new vehicle.) But 24% of their PVs, and 25% of their total minutes, came from these "auto intenders." One in four ads at this site will be seen by someone who is in the heaviest 20% of users of automotive manufacturer sites in the same month. When we expand our behavioral target to include the heavy and moderate users of automotive manufacturer sites, then about half the ads on this site will be seen by automotive intenders.
Two final points. One, when I talk about looking at the composition by Page Views here, I really mean, look at composition based on a measure of total consumption as opposed to the total UV (or "cume") audience. If you are concerned about the impact of AJAX on the efficacy of the PV as a metric, the same principle applies with respect to minutes as with pages. In radio, for example, the 36% of a station's cume who comprise the station's core audience consume 72% of that station's quarter-hours of listening.
And two: How about those Giants?