Both metrics contain valuable information, but they are not the same. Sometimes, an AudienceReport Campaign Measurememt provides another set of campaign demographics than one would expect based on the average user profiles of campaign site(s).

Why is this?

Multiple reasons can be at play. There are the obvious variations stemming from differences in traffic patterns during the campaign period and the site centric measurement period (typically a quarter or a month). Also, traffic can be sliced by use of, for instance, different prediction behavioral targeting techniques etc.

But there can also be subtler, harder to grasp, reasons arising from a more complex traffic composition on the campaign sites than often discernable in a site-centric average user profile.

Let us provide an example:

Recently, we had a campaign in Norway where one of the placements were a big Norwegian garden and homeowner site owned by one the major publishers. Based on the AudienceReport Campaign Measurement we could se that around 58 % of the impressions were hitting people above 55 years.

This estimate collided with the average user-profile of the site stating that around 25-30 % of users would be 55 or more. Fortunately, this site was using one of our other services enabling it to transfer our Audience data to the site´s Google Analytics account (read more)

This way, GA analytics could be combined with our Demographics. For instance, allowing us to break down age and time spent on the site. Below a table with GA and AudienceReport numbers crossed:

Hey, old people spend much more time on the site than youngsters. Consequently, they also have more pageviews. The same pattern is seen when checking out the demographics of guest-, medium- and frequent users:

Older people just seem to love this site!

All this implies that even though only 25-30 % of average users are 55+, people in this age bracket are more frequent users and they spend much more time on the site. Now, not surprisingly, a lot of the impressions on campaigns run on this site is bound to go to old people. In fact, the site is a very attractive platform for campaigns toward this target group because old folks are very engaged, spend a lot of time on the site and often come back. As an advertiser, you get a lot of eyeball time on each of your impressions.

Conversely, as for young people. Maybe try out another site.

Conclusion

Having an average user profile of this site did the advertiser no good. But making a Campaign Audience Measurement gave precise information about who the impressions actually met in this campaign.