Forget the A list, the B list and the C list. Scientists have invented a new way of rating celebrities - using a mathematical formula that ranks them according to selling power.
The new formula can be used by businesses to rate the effectiveness of celebrity endorsements. The brainchild of a US academic, it helps advertisers to decide if Beckham is better than Connery, or Hurley superior to Madonna, in helping to shift a product.
"Choosing a celebrity as an endorser for your product simply because they are the flavour of the month is risky and decidedly unwise," says Dr Cynthia Knott, inventor of the new celebrity formula. "A more precise indicator of effectiveness is needed because it is imperative that corporations make wise choices when deciding on a spokesperson for their product or service.''
As many as one in five TV commercials use celebrity endorsements, which can be extremely expensive - not only in the cost of hiring the celebrity, but also in how the celebrity can affect the image of the advertiser.
The formula - using matrix algebra, eigenvectors and pairwise comparisons - that she and fellow researchers at George Washington University have created is based on rating each celebrity for a number of qualities: credibility, attractiveness, trustworthiness, expertise, likeability and familiarity.
The ratings on each of the traits are fed into a computer program, which comes up with the name of the best celebrity endorser.
When The Independent on Sunday fed the names into the computer, Sean Connery came out on top followed closely by David Beckham.
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