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.
When an advertiser makes a superlative claim, they suggest that their business, or an aspect of it, is superior to that of their competitors. A superlative claim can be a broad claim, such as “the best” or ‘best-selling’, or a specific claim, such as “the most customers” or “the highest rated”.
The ASA will consider unqualified superlative claims to be comparative claims against all competing products. The rules on making comparisons with identifiable competitors will therefore apply (Rules 3.33 - 3.37). See Comparisons: general.
Superiority claims must be supported by evidence unless they are obvious exaggerations (puffery) or claims that consumers are unlikely to take literally. In those instances, the claim is allowed provided it does not materially mislead (Rule 3.2).
Similarly, marketing communications must not imply that expressions of opinion are objective claims (Rule 3.6). See Types of Claims: Puffery and expressions of opinion for further information.
Puffery and expressions of opinion
Substantiation
As with all comparisons, superlative claims must be presented in a way which is unlikely to mislead. 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 (Rule 3.7).
The likely interpretation of an unqualified superlative claim will depend on the product or service advertised and the context in which the claim appears. The nature of the evidence required to substantiate superlative claims will depend on how it is likely to be understood by its audience.
Unless the nature of the product or the context in which the claim appears gives the claim another meaning, or the meaning is ambiguous, “no. 1”, “best-selling”, “leading” and other similar claims are generally treated as objective best-selling claims, particularly if they are unqualified. Claims which will be interpreted as best-selling claims are likely to require evidence regarding market share, unit sales, or both. For instance, the ASA determined that the AA’s claim to be ‘The UK’s number 1 breakdown service provider’ would be interpreted to mean that the AA had the most members compared to their competitors in the UK breakdown insurance market. The ad was considered misleading, because the AA did not have the membership figures of their competitors required to make a like-for-like comparison with their own (AA Ltd, 20 July 2022). By way of further example, the ASA upheld a complaint about the claim “#1 holiday website on the planet”, because the advertiser did not provide evidence to demonstrate that it had the largest turnover of holiday rentals when compared to their global competitors (Rental Republic Ltd, 19 January 2022). See also (Ryanair Ltd, 7 February 2018).
When making “best” claims, advertisers must consider a consumers’ likely understanding of the claim to determine the type of substantiation required. For instance, the ASA thought consumers would interpret ‘On the network voted Britain’s Best for Coverage’, alongside the uSwitch logo, to mean O2 had won the best network for coverage category at the uSwitch awards. The ASA considered this would be seen as a comparative claim with the rest of the market, and consumers would therefore expect it to be supported by objective data. However, the methodology only required consumers to appraise their own provider, and the criteria was broad. The data appeared to be highly subjective. The ASA said the CAP Code required comparative claims to be based on objective data, and because it was unclear how this consumer perception survey could deliver objective data, the claim was deemed misleading (Telefonica UK Ltd t/a O2, 22 September 2021) . The ASA has also deemed “best price” (UK Life Protection, British Life Cover Quotes, British Life Benefits, 22 February 2023), “best available tickets” (Ticketmaster UK Ltd, 03 January 2018), “The Best Alarm Technology on the Market” (Verisure Services (UK) Ltd, 01 June 2022) and ‘The UK’s best value mobile’ (Utility Warehouse Ltd, 08 August 2018) misleading in the absence of evidence to support the respective claims.
Even for more nuanced superlative claims, the ASA will expect them to be substantiated if consumers are likely to interpret them as objective. For example, an advertiser described their home beauty device as ‘the world’s most powerful’, both in isolation, and as part of a sentence referencing the effectiveness of the device in turning ‘back the aging clock’, and the ability to ‘transform…skin in weeks’. The ASA expected the advertiser to hold evidence to show that their device was the most effective for treating the visible signs of aging, and other skin conditions. The ASA thought consumers would interpret the claim in terms of the device’s efficacy, rather than its physical power output, and therefore expected any substantiation to reflect this (Lyma Life Ltd, 26 June 2024). For more unsubstantiated superlative claims, see RoofSURE Ltd, 19 April 2023 in respect of a ‘world’s most efficient claim’ and Waterwipes UC, 8 March 2023, in which the ASA ruled on a ‘world’s purest…’ claim.
Self-reported consumer data will not be sufficient to support a claim that would otherwise require objective substantiation. Marketers should not rely on consumer perception data, or the fact that they have received awards, to support claims for which they do not hold objective substantiation (Telefonica UK Ltd t/a O2, 22 September 2021 and Hutchison 3G UK Ltd t/a 3, 24 February 2021). For further advice see Comparisons based on awards and surveys.
For advice on specific types of claims see Types of claims: Best, Types of claims: Best-selling, Types of claims: No.1, Types of claims: Leading and Types of claims: Premier.
Verifiability
When making comparisons with identifiable competitors, as well as holding evidence to substantiate any claims, advertisers must ensure that their meaning is clear, that they compare products or services intended for the same purpose, and that the claims are verifiable (rules 3.33 – 3.37). For detailed guidance on these requirements see Comparisons: Identifiable competitors and Comparisons: Verifiability.
Because objective superlative claims are, by their nature, comparisons with all competitors, they are likely to be considered comparisons with identifiable competitors and must be verifiable.
To make a claim verifiable, the advertiser should set out the relevant information in the ad or signpost how the information used to make that comparison can be checked by the audience. The information required to make a claim verifiable will depend entirely on the specific comparison and the evidence used to support it. Marketers should include, or direct consumers to, sufficient objective information and data to ensure that consumers are able to check the claims are accurate for themselves. For examples of unverified superlative claims, see RoofSURE Ltd, 19 April 2023 in which the ASA ruled on a ‘world’s most efficient claim’ and Waterwipes UC, 8 March 2023 in respect of a ‘world’s purest…’ claim.
If verifying the comparison requires specialist knowledge, consumers should be able to get a knowledgeable and independent person or organisation to verify the comparison for them. Providing incomplete or inaccessible information, for example, behind a paywall, is unlikely to be considered sufficient (Procter & Gamble UK, 27 May 2020).
Puffery and expressions of opinion
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.
If the basis of a superlative claim is unstated, and 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 ORIGINAL AND 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 using subjective claims or stating matters of opinion and should ensure that these will not mislead. For example, Sky did not intend for the claim ‘the perfect network’ to be an objective or superiority claim about network capabilities or performance. Instead, they believed consumers would understand the claim as Sky’s own opinion, and with a degree of puffery. However, the ASA decided that consumers would understand the claim to be an objective one, and therefore capable of objective substantiation (Sky UK Ltd, 8 June 2022).
See Types of Claims: Puffery and expressions of opinion for further information.
For sector specific advice see Comparisons: Telecoms and Comparisons: Travel.