• by Masha Geller , April 1, 2002

In the last few months, nearly two dozen researchers, investment banking firms, analysts and ad agencies have reported estimates of online advertising revenue for 2001. But the range is wide, from a low of $2.5 billion to a high of $19.0 billion – enough to make anyone’s head spin.

Well, today eMarketer, announced that after an extensive review, the firm has selected the Interactive Advertising Bureau's (IAB) Internet Ad Revenue Report as the benchmark source for measuring the growth of Internet ad revenue. Accordingly, eMarketer will hold its future projections accountable based on the online ad revenue figures reported in the IAB's Internet Ad Revenue Report, which is conducted independently by the New Media Group of PricewaterhouseCoopers.

"With over 20 different researchers offering up 20 different sets of numbers, no wonder advertisers, their agencies and publishers have been confused," said Geoffrey Ramsey, CEO, eMarketer. "However, when certain outliers are removed and apples-to-apples comparisons are made between numbers, allowing for differences in definitions, estimates from most of the leading research firms closely match those reported by the IAB/PwC."

As an example of how different definitions can distort comparisons, consider Morgan Stanley , which reported 2000 revenues of $7.4 billion. This figure, however, excludes barter and email, which constitute 10% of total dollars. If these items are added back in, the resultant total is the same figure as reported by the IAB for that year.

So what are the numbers? Eight leading research and analyst firms currently report spending figures that are in alignment with the levels reported by IAB/PwC -- approximately $8 billion for 2000 and between $7.0 - $7.9 billion for calendar year 2001.