Interesting post by Forbes’ Marc Babej about how well celebrity endorsements work (or don’t work):

77% of respondents [to an Adweek/Harris Interactive poll] claimed that “when a sports star, movie star or other celebrity endorses a product” they are no more or less likely to buy it. 14% stated they are less likely to buy. Only 4% stated they are more likely to buy. What’s more, these results were remarkably consistent across age groups and gender.

The intriguing part: his point about how the question simply underscores the challenges market researchers face when trying to gauge this sort of metric.

[O]pinion surveys operate on three big assumptions:

• a) that respondents are aware enough of their, often subconscious, mental processes to assess their reaction
• b) that they will openly admit  their views; and
• c) that their stated views are predictive of their actual behavior

So what should we take from this new research? Babej suggests a different standard by which to measure the effectiveness of celeb endorsements:

1. Are celebrity endorsements relevant for the product category? In highly image-driven consumer categories such as fashion, perfume or liquor, celebrity endorsements can be credible. For sporting goods, endorsement by an athlete can work wonders (just ask the good people at Nike and Adidas). But in categories that require more consideration, such as financial services, a celebrity endorser isn’t likely to have much of a positive impact – for the simple reason that movie stars or athletes aren’t considered authorities in these areas
2. Is the celebrity endorser credible for a given product or category? Angelina Jolie is quite credible for Louis Vuitton – she’s a style icon, and it’s not too hard to imagine her wearing Vuitton products by choice? James Gandolfini would be credible for cigars – it doesn’t require a whole lot of imagination to see the Tony Soprano actor smoking a Montecristo. Now reverse the roles and the relevance goes up in smoke
3. Is the celebrity endorsement cost-effective? The devil is in the details, here: campaign budgets vary, and so do celebrity price tags. But as a general matter, the kind of celebrities that could make a difference don’t come cheap

Conclusion: celebrity endorsements as an advertising tactic should be approached with caution… but not because of consumers’ self-reported likeliness to be swayed by them.