Note: This advice is given by the CAP Executive about non-broadcast advertising. It does not constitute legal advice. It does not bind CAP, CAP advisory panels or the Advertising Standards Authority.

The most common way a superlative claim is expressed without the basis of the claim being clear is by the use of the word “best”, as, for example, in “The best widget in the world” or “Product X is best for you”. If the rest of the advertisement does not clarify the criterion used for the claim, the ASA is likely to regard the claim as a subjective one. For example, in 2005, the ASA rejected complaints about the claim “The best keeps getting better” and “… sell only the best in the business” on the grounds that they would be seen as the advertiser’s opinion (Alphason Designs Ltd, 6 April 2005).

The use of an unqualified “best” claim does not, however, mean marketers are on safe ground. For example, in 2004 the ASA asked an advertiser to change the claim “best instructors” to “some of the best instructors” (1st Class Motorcycle Training, 10 November 2004) and upheld a complaint against the claim “best agent” because the assessment did not include all agents and was carried out by an organisation that was associated with the advertiser (Rook Matthews Sayer, 16 April 2003). The ASA also upheld a complaint against claims to offer the “best stairlift” (Companion Stairlifts Ltd, 16 June 2004) and against the Daily Mail’s claim of “unrivalled TV listings with six large format pages devoted to every day’s programmes”. The ASA interpreted the claim as being comparative against all other UK daily newspapers but the advertisers sought to support the claim with a comparison with one competitor only (Associated Newspapers, 2 April 2003, complaint 4).

In 2013, the ASA ruled that the Cadogan Clinic's claim that their medical and surgical consultants were "the best in Europe" was objective, because readers were likely to think their consultants had been shown to be better than their peers, for example in terms of their surgical success rates, (The Cadogan Clinic, 27 February 2013).

If the criterion for the “best” claim is stated, we regard the claim as an objective one, capable of substantiation: for example, “Best selling” (Highbury House Communications plc, 18 February 2004, and Emap Automotive Ltd, 23 July 2003) “best fuel efficiency”, “The widget that’s best for long engine life” or “Our cleaning powder is best for greasy stains”.

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