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 CAP Code requires advertisers to hold documentary evidence to substantiate claims that consumers are likely to regard as objective and that are capable of objective substantiation (Code rule 3.7).

Code rule 3.2 states that obvious exaggerations ("puffery") and claims that the average consumer who sees the marketing communication is unlikely to take literally are allowed provided they do not materially mislead. Marketers are not expected to hold documentary evidence to prove claims which will not be regarded by consumers as objective, or capable of objective substantiation. This may include claims which consumers will interpret as an opinion about the product and service, such as “my favourite”, or those that refer to aspects of a product or service which are based on personal subjective preference, such as look, taste, or feel.

Generally superlative claims will be considered comparisons, however, if the claim is unlikely, in the context in which it appears, to have an objective meaning to consumers, the ASA may regard the claim as subjective. In 2020 The ASA considered that the claim “THE BEST SINCE 2004”, in an ad for a pillowcase would be understood as a subjective expression of Slipsilk’s opinion about their product and was therefore not capable of objective substantiation (Slip Enterprises Pty Ltd t/a Slipsilk 11 March 2020).

Marketers should be cautious when stating matters of opinion and should ensure that these will not mislead; marketing communications must not imply that expressions of opinion are objective claims (Code rule 3.6). Even if a claim is clearly a matter of opinion, the claim must not mislead. In 2005 the ASA upheld a complaint about the claim “the ultimate broadband experience”. Although it accepted the claim was the advertiser’s opinion, the ASA considered the incidence of severe customer dissatisfaction with the service was enough to make the claim misleading (Bulldog Communications Ltd, 2 March 2005).

Marketers should not try to present objective claims as subjective opinions. For example, by putting quotation marks round an objective claim, prefixing a claim with “users thought” or making objective claims in testimonials. Even if a claim is presented as an opinion, if it is an objective claim it must be supported by evidence which substantiates the claim (rule 3.7).

Testimonials expressing opinions may be used but, if they relate to a claim that can be measured objectively (for example, a product’s efficacy), the claim should be supported with independent evidence of its accuracy. An ad for CEASE therapy which included testimonials was upheld by the ASA, who considered that visitors to the website would understand the claims in the testimonial as factual, and as relating to the objective benefits of CEASE therapy.  They therefore considered that the ad made claims for the efficacy of CEASE therapy in treating autism, and they had no evidence to support this claim (Teddington Homeopathy, 22 July 2015). See Testimonials and endorsements.

Some claims might be considered subjective in one context but objective in another. the ASA has considered claims such as “best”, “favourite” (best-selling) and “ultimate” (best-performing) objective in some contexts but subjective in others. See Types of claim: Best and Types of claim: Best-selling. Marketers should read the guidance on Comparisons: general, before making claims which may be considered comparisons.

Certain types of claims, such as those made by pressure groups, charities or campaigners are likely to promote one point of view over another. Such groups are not obliged to present a balance of for and against arguments in their ads, and the Code states that the ASA does not arbitrate between conflicting ideologies. If marketers are obviously expressing opinions about their beliefs, the ASA is unlikely to intervene unless marcoms mislead or offend (Lydd Airport Action Group, 27 June 2007). However, marketers are still expected to ensure their claims are accurate and backed by evidence (Friends of the Earth Ltd, 10 July 2019 and Both Lives Matter, 2 August 2017).

See also Substantiation, and Types of claims: Obvious exaggerations and puffery.


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