I believe it is because the article references an Article One Partners white paper entitled "LTE Standard Essential Patents Now and in the Future". And that white paper includes IDCC throughout, but in the specific section that the article lists the top 5, IDCC was #6 on the list.
The white paper is old news -- it came out in February.
Here's my post from IV back on February 20th with charts & tables from the white paper, comments, and a link to the entire report (PDF document): http://bit.ly/Irrj09