A question I am often asked is does advertising actually work.
According to WARC, who have launched an ROI Benchmarker, high-performing advertising campaigns generate an average of 180% ROI within the first year. This means that the real impact is likely to be even higher. (According to WARC, it is likely to be twice as high as the payback in the short term.
The ROI Benchmarker database is based on the data drawn from advertising-based case studies since 2000. Bear in mind that only successful campaigns are likely to have been submitted as case studies, but this does provide a useful benchmark.