Comscore’s Fishy Facebook Numbers

by alec on July 6, 2007

Comscore published some web site usage metrics for Facebook yesterday.  While the aggregate visitor growth of 89%, year over year, from 2006 to 2007 was impressive, the demographic information was puzzling, and just doesn't add up. 

Facebook.com Demographic Profile

Unique Visitors  (000)
May 2007 vs. May 2006
Total U.S. – Home/Work/University Locations
Source: comScore Media Metrix  

 

 Age Segment

Facebook.com

May-06

(000)

May-07

(000)

Percent Change

Total Audience

Unique Visitors (000)

14,069

26,649

89%

    Persons: 12-17

1,628

4,060

149%

    Persons: 18-24

5,674

7,843

38%

    Persons: 25-34

1,114

3,134

181%

    Persons: 35+

5,247

10,412

98%

 

Facebook themselves published some data in February at the Facebook Tech and Tasting in Silicon Valley. I have transcribed from photographs of their slides into a table, reproduced below, and compared it to the Comscore data.  Clearly something is amiss.  For example, Comscore's May numbers appear to show substantially lower growth rates in the under 18 and 25-30 markets than Facebook's own data would suggest, as well as a substantial drop in the core 18-24 demographic. 

Taking into account that Facebook is measuring users, and Comscore visitors, some of the discrepancies can be explained away by the school year.  For instance, the fact that there were 12 million users in February in the 18-24 demographic, but just 7.8 million reported visitors in May can be explained by noting that the college year is over at the end of April.  Kids are moving, finding summer jobs, and so on.

In the under 18 category, and the 25 to 34 category, apparently robust growth in January and February isn't reflected in visitor statistics in May. A possible explanation is that a percentage of users sign up for Facebook, and then don't use it much.  Again, very plausible.  It's certainly the case in our household, where two out of four Facebook users are frequent visitors, and the other two never visit.

But in the 35+ demographic how does one go from 780 thousand users signed up in February to 10.4 million unique visitors in May? Moreover, how is it that Comscore can report over 5 million visitors were age 35 and older in May 2006, when Facebook claims only 55,000 signed up in that demographic in July 2006. 

And finally, Comscore's numbers don't add up.  Literally!  They're reporting 26,649,000 unique visitors, but their four categories add up to 25,449,00. Who are the phantom 1.2 million unique ageless visitors?

Something doesn't smell right.  Anybody from Facebook or Comscore care to comment?

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