Sunday, April 13, 2008

More great statistics from Procter and Gamble (Micro Statistics Tutorial 08)

Advertising Standards Authority (UK): 26 March 2008, Adjudication over Cat Food Advertisement (Iams Cat Food). More worthwhile statistics from Procter and Gamble:

The advertisements stated:
  1. "Vets know catering to all your cats' different needs isn't easy ... 8 out of 10 vets recommend Iams
  2. Voted No.1 recommended dry cat food brand available in supermarkets
  3. Small print at the bottom of the ad stated "*Based on an independent survey of vets at the Congress of the British Small Animal Veterinary Association on complete dry cat foods available in supermarkets (April 2007)".
The Advertising Standards Authority noted that:
  1. The survey asked vets if they would recommend any dry dog food, dry cat food or wet cat food brands. Only 31% of the participating vets (31% of 334) in fact recommended Iams.
  2. Furthermore, the survey questions allowed participants to select a number of brands; they did not select only one brand.
  3. Two other brands had more recommendations but these brands were available in pet food shops.
  4. 80% of vets who recommended a brand of dry cat food available in supermarkets included Iams amongst the selection of products recommended, but not necessarily over those other products
Action: ASA told P&G to remove the claims "8 out of 10 vets" and "Voted No. 1 by vets" from future advertisements. The ASA did not comment on the irrelevancy of the survey (it should have surveyed cats), the nature of the sample, the post-hoc hypothesis, lack of any P value or who commissioned the "survey". For contaminated P&G catfood, see here.

Tutorial: Try to reconstruct the statistics from the ASA report.

See here for Collated Micro-Statistics Tutorials

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1 comment:

Monica Cassani said...

my cat got a urinary infection...a bad one because of eating Iams... the vet specifically said it was to high in a certain mineral and that a higher quality cat food was needed.

Not all cats are predisposed to this kind of urinary infection but it's just better to stay away from Iams if you want to avoid making your cat sick.