Do you buy Activia because Jamie Lee Curtis says you should? Or a Sony TV because Peyton Manning is their pitchman? What about that stash of Extenze you keep in the bedside table — did you purchase that on the recommendation of Jimmy Johnson? A new study shows that the answer to all these questions is probably a big “no.”

The study by Ace Metrix, looked at 263 unique nationally televised ads featuring celebrity endorsements from 2010. The ads represented 16 industries and 110 brands and all the ads were tested within 48 hours of their first national airing in an attempt to get an immediate, untainted reaction.

The ads were scored in eight different categories, including relevance, watchability, persuasion and desire. And in ever single category, the ads featuring celebrities fared worse than the non-celebrity control group of ads.

Writes Ace’s Peter Daboll on AdAge.com:

[T]ime and time again we observed incredibly low effectiveness scores of TV ads starring celebrities. From Tiger Woods to Donald Trump, we found that with rare exception, celebrity endorsements were largely ineffective and failed to yield the benefits popular wisdom promises.

The five celebrity ads that fared the worst were:
1. Tiger Woods “Did You Learn Anything” spot for Nike
2. Lance Armstrong’s “No Emoticons” ad for Radio Shack
3. Kenny Mayne’s “Good Segment” ad for Gillette
4. Dale Earnhardt Jr.’s “Coverage at the Right Price” spot for Nationwide Auto Insurance
5. Donald Trump’s “Making Timmy a Mogul” ad for Macy’s

Daboll says one of the most common problems people cited with celebrity ads was confusion about what was being sold. For example, the Lance Armstrong Radio Shack ad makes no mention of the electronics store outside of the branding on Lance’s cycling uniform and could be for just about any product.

Concludes Daboll:

The bottom line is that good ads stand on their own, and this study empirically shows that a celebrity has little to no impact on an ad’s effectiveness. In fact, regardless of gender or age, ads without celebrities out-performed ads with them…

Just because a celebrity is incredibly popular and achieves fabulous box-office returns and critical accolades does not mean they will provide a similar boon to brands in advertising.

While we’re on the topic of badvertising, remember that we’re already taking nominations for the next Worst Ad In America awards. So the next time you see an ad that makes you want to hurl your shoe at the TV, shoot us an e-mail at tips@consumerist.com with “WAIA” in the subject line.

Celebrities in Advertising Are Almost Always a Big Waste of Money [AdAge]

Celebrity Advertisements: Exposing A Myth Of Advertising Effectiveness [Ace Metrix]

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