The data comes from ZenithOptimedia's Touchpoints ROI Tracker, a comprehensive project comprising over 300,000 interviews across 34 countries and covering more than 4,000 brands in 126 product and service categories.
ZenithOptimedia is making the data available publicly for the first time this month.
Consumer touchpoints were each given a "contact clout factor," a number on a scale of 1 to 100 that indicates the relative influence of the touchpoint on purchasing.
Recommendations from family and friends led the pack with an average score of 84. TV ads and Internet search were next, with an average score of 69 and 67, followed by magazine ads at 60, newspaper ads at 55, outdoor ads at 45, radio ads at 42, and Internet banner ads at 41.
Though word-of-mouth may be one of the greatest influences on brand choice, marketers still face a great challenge is making it scalable, said Bruce Goerlich, ZenithOptimedia's president of strategic resources, North America.
"Word of mouth is incredibly powerful, but we as an industry are not doing as good a job as we could do in generating it," he said.
TV is tops for branding
The ROI Tracker also measures brand association, or the percentage of consumers who say they have seen or heard of a brand though a touchpoint in recent months.
In the brand association category, TV is still king. The average brand advertising on TV is recalled by 22% of category consumers. Magazine ads follow with 16% of category consumers, and newspaper ads and family and friend recommendations are recalled by 13% each. Internet search follows with 12% of category consumers, followed by outdoor ads at 9% and Internet banner ads and radio ads at 7% each.