I am designing a Customer Lifetime Value Financial model for client. We were digging into his website traffic data and found a disparity in some of the traffic data provided through various sources which would drive one to quite different conclusions. This was frustrating!
I did a little research and found the following data in the November 29, 2010 issue of Brandweek. The article listed Nielsen, comScore, Compete, and Quantcast numbers with the firms' internal data. With different filters and methodologies being used to determine what is a unique visit, I wasn't surprised about some variance. However, there are big differences. Even Nielsen has reported that there data has under counted visits. Here is some data for some popular sites which highlights some of the challenges. There are many stories about websites contesting their
Unique Audience Numbers in Millions*
Internal Data 30.0 4.8 44.2 190.0 34.2 NA
Quantcast 25.0 3.9 24.7 59.1 22.7 20.6
comScore 21.7 2.9 23.1 25.1 34.3 42.7
Compete 13.6 1.9 12.3 25.8 NA 0.136
Nielsen 12.3 NA 13.0 20.1 NA 21.1
* Other than Nielsen, data is for October 2010. ESPN does not disclose traffic.
For the purchasers of this data, there is a lot of confusion as to who to believe and how do you deal with the data disparity. Unique visits is one of the measures used to monitor the effectiveness of your social media strategy. Have you seen this disparity with your sites? I have with my alumni association web site.