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 interpretation of a “best” claim will depend on the product or service advertised and the context in which the claim appears. Marketers intending to make a “best” claim should consider how consumers are likely to interpret the claim in the context of the ad.

Before making any ‘best’ claims in advertising, marketers should consider the following:

  1. How will consumers interpret the claim?
    • Is it puffery?
    • Is it objective?
    • Is it a comparison with identifiable competitors?
  2. If it is objective, make sure you can substantiate it.
  3. In addition, when making a comparison with identifiable competitors comply with Rules 3.33 – 3.37.

How will consumers interpret the claim?

  • Is it puffery?

Obvious exaggerations (“puffery”) and claims that the average consumer is unlikely to take literally are allowed provided they do not materially mislead (Rule 3.2). 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.

The ASA considered that the claim “THE BEST SINCE 2004”, in an ad for a pillowcase would be understood, in the context of the ad, 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).

The ASA will assess a consumer’s likely interpretation of a claim, rather than the marketer’s intention. Marketers intending to make a “best” claim should therefore take particular care to ensure their claim is not likely to be understood as an objective claim. See Types of claimsPuffery or expressions of opinion for more information 

  • Is it objective?

If consumers will understand a "best" claim to be a reference to an objectively measurable feature of the product or service advertised, the claim will be considered an objective one.

If the criterion for the “best” claim is stated, and that criterion is objective, the claim will be considered objective too. In 2018, the ASA considered that consumers would interpret the claim “The UK’s best value mobile” to relate to the features integral to the nature of a mobile phone service: minutes, texts and data. Because the advertiser did not offer more data, minutes and texts than all other UK mobile tariffs relative to the costs of the tariffs, the ASA found the claim to be misleading (Utility Warehouse Ltd, 08 August 2018). For similar rulings, see two Vodafone cases (here and here), and best-selling’.

The likely interpretation of an unqualified “best” claim will depend on the product or service advertised and the context in which the claim appears. For example, in 2013, the ASA considered the claim that Platinum tickets were the “best available tickets”. Whilst the ASA appreciated that what was considered ‘best’ may depend on individual preferences, they said consumers were likely to view the claim to mean that those tickets offered a tangible benefit compared to other tickets because, for example, they were closer to, or offered a better view of, the stage. The ASA found the claim to be misleading, as whilst the Platinum tickets were among some of the best seats at the venue, they did not offer a tangible benefit compared to some of the general seating tickets. Indeed, in some instances, the Platinum tickets offered an objectively worse experience (Ticketmaster UK Ltd, 03 January 2018).

  • Is it a comparison with identifiable competitors?

Marketers do not need to explicitly identify the competitor or product they are comparing with to be subject to the rules on comparisons with 'identifiable' competitors. The ASA’s interpretation of ‘identifiable’ competitors is broad. If a consumer can identify at least one competitor that is being compared, whether or not they are identified explicitly in the ad, Rules 3.33 – 3.37 will apply. Generally, unqualified “best” claims will be viewed as comparisons with all of an advertiser’s competitors. See Identifiable competitors below for more information on the applicable rules, and also our dedicated guidance on Comparisons: identifiable competitors.

If it is not possible to identify a competitor, Rules 3.33 – 3.37 will not apply. Instead, Rule 3.38, which states that a comparison with an unidentifiable competitor must not mislead, or be likely to mislead, the consumer, will apply. See Comparisons: general for further information.

Substantiation

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 nature of the evidence required to substantiate “best” claims, or any claim likely to be understood in the same way, will vary depending on its likely interpretation in the ad. To substantiate superlative, top parity or “best” claims, advertisers are likely to be required to hold evidence which relates to their competitor’s product or service and which demonstrates how its own product/service compares.

By way of example, the ASA considered ‘Best Policy, Best Price…’ to mean that the life insurance policy advertised was the most suitable product across the whole market, and that the advertiser would provide said policy at the cheapest price compared with other providers. In the absence of evidence relating to the policies, and evidence comparing their prices with those of other providers, the claim was deemed misleading and unsubstantiated (UK Life Protection, British Life Cover Quotes, British Life Benefits, 22 February 2023). Similarly, “The Best Alarm Technology on the Market” would be understood to mean that the advertiser’s alarm systems were technologically superior to all other providers in the UK. Because the advertiser only had evidence relating to three competitors, and a relatively small number of features offered, this was not considered adequate to substantiate the claim (Verisure Services (UK) Ltd, 01 June 2022).

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. 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). See also Vodafone Ltd, 28 July 2021 and Hutchison 3G UK Ltd t/a 3, 24 February 2021.

For further advice on comparative claims made based on surveys and third-party awards see Comparisons: Awards and consumer surveys and Substantiation: Consumer surveys and sample claims.

Identifiable competitors

Comparisons with identifiable competitors must not mislead, or be likely to mislead, the consumer about either the advertised product, or the competing product (Rule 3.33), must compare products meeting the same need or intended for the same purpose (Rule 3.34), and must objectively compare one or more material, relevant, verifiable and representative feature of those products (Rule 3.35). For detailed guidance on these rules see Comparisons: identifiable competitors.

To make a claim verifiable (as required under rule 3.35), 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 must be readily available, and sufficient for consumers to be able to verify the comparison.

For instance, because an ad using the claim “The UK’s Best Network” did not include, or direct consumers to, objective evidence to support the claim, the ASA concluded the claim was not verifiable (Vodafone Ltd, 28 July 2021). Another similar case, Vodafone Ltd, 28 July 2021, also discusses the need for objective comparisons to be verifiable.

For further detailed advice, see Comparisons: Verifiability.

For sector specific advice see Comparisons: Telecoms and Comparisons: Travel


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