The revised forecast, the first to be issued since Magna recalibrated its methodology for estimating ad spending from an agency billings-centric process to one that is based on actual advertising revenues derived by the media, may make it difficult to compare with other industry forecasters, but Magna global forecasting chief Brian Wieser has claimed it is a more honest and holistic view of the advertising economy. As part of his recalibration, he has also divided total ad spending for each medium into three discrete buckets of national, local and so-called "direct" based advertising revenues.

On those bases, the 2009 outlook for that national online ad economy has improved slightly from last summer, but the scenarios for local and direct of grown worse.

Wieser now projects that national online advertising revenues will decline 9.8% to $5.578 billion in 2009. That compares with his July outlook of a decline of 11.1% for national online ad spending in 2009.

Direct online ad spending, the biggest component of the U.S. online advertising mix, now is expected to grow 2.5% to $13.863 billion in 2009, a downward revision from July, when Interpublic projected it would grow 2.9% in 2009.

Local online ad spending is now expected to decline 11.1% to $3.403 billion in 2009. In July, Interpublic had forecasted that local U.S. online ad spending would decline only 9.3% during 2009.

Despite the discrete category fluctuations, Interpublic believes the overall U.S. advertising economy has stabilized and has actually improved from its last snapshot in July, and that it will continue to improve as the overall U.S. economy continues to expand.

"As a result, we are moderating our 2010 advertising forecast and now expect normalized advertising revenues (excluding local TV political and national TV Olympic revenues) to decline 1.3% next year," the agency said in this morning's announcement. "This compares with our previously published expectations for a decline of 2.1% during 2010. In total, we expect suppliers to generate $159 billion of normalized advertising revenue next year.