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.

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. Additionally, any comparisons with identifiable competitors must be verifiable and comply with other relevant comparisons rules (3.33 – 3.40). See also Comparisons: Identifiable competitors and Comparisons: General

Claims that the average consumer is likely to understand as an obvious exaggeration (puffery) or claims which consumers are unlikely to take literally are allowed provided they do not materially mislead (3.2).

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.

The sections below give guidance on each of these stages.

How will consumers interpret the claim?

Is it puffery?

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.

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 that it is not likely to be understood as an objective claim. See Types of claims: Puffery

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, and the advice in the section on substantiation, below, will apply.

If the criterion for the “best” claim is stated, and that criterion is objective, then the ASA will regard the claim as an objective one. 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, and because the advertiser did not offer more data, minutes and texts than all other UK mobile tariffs relative to the costs of the tariffs, found the claim misleading (Utility Warehouse Ltd, 08 August 2018). See also, “Best-selling” (LittleLamb Ltd, 11 February 2015)  and “best price” (The Carphone Warehouse Ltd, 03 August 2016).

The likely interpretation of an unqualified “best” claim will depend on the product or service advertised and the context in which the claim appears. The ASA considered the claim “best available tickets”. Whilst they appreciated that what was considered ‘best’ may have depended on individual preferences, they considered 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 (Ticketmaster UK Ltd, 03 January 2018).

Is it a comparison with identifiable competitors?

Marketers do not need to identify explicitly the competitor or product that they are comparing with to be subject to the rules on comparisons with 'identifiable' competitors, and 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 it is identified explicitly in the ad, rules 3.33 – 3.37 will apply. Generally, unqualified superlative “best” claims will be comparisons with all competitors, and therefore, it will be possible to identify competitors. See the section on ‘comparisons with identifiable competitors’ below, and our general guidance on Comparisons: identifiable competitors.

If it is not possible to identify a competitor, rules 3.33 – 3.37 will not apply. Marketers must still ensure that these types of comparisons do not mislead (3.38), and objective claims must be supported by evidence (3.7). See Comparisons: general.

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.

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

The ASA considered that the claim “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 recieved awards, to support claims for which they do not hold objective substantiation. See 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” (3.33), “must compare products meeting the same need or intended for the same purpose” (3.34), and “must objectively compare one or more material, relevant, verifiable and representative feature of those products” (3.35). For detailed guidance on these rules see Comparisons: identifiable competitors.

The ASA upheld complaints about the claim “on the network voted Britain’s Best for Coverage” because the comparison was based on customers’ subjective perceptions of their own networks, and the advertiser did not hold evidence that a range of networks had been rated based on a robustly conducted comparison of a range of appropriate, relevant and objective performance measures, which was a breach of rule 3.35 (Telefonica UK Ltd, 22 September 2021).

Comparisons with identifiable competitors 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. For detailed advice on this requirement, see Comparisons: Verifiability.

The information must be readily available, and sufficient for consumers to be able to verify the comparison. The claim “The UK’s Best Network” needed to be backed up by objective evidence which showed Vodafone’s network had been found to perform better in technical aspects such as coverage and reliability than the rest of the market. Although the ad did include information about the customer survey used to support the claim, because the ad did not include, or direct consumers to, objective evidence to support the claim, the claim was not verifiable (Vodafone Ltd, 28 July 2021).

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


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