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 ASA and CAP recognise that comparisons help give customers valuable information as well as encourage competition between advertisers. But, as with all ads, it is important that they are clear and easy for consumers to understand and they comply with the relevant legislation.

The CAP Code requires that comparisons with identifiable competitor products “must objectively compare one or more material, relevant, verifiable and representative feature of those products” (rule 3.35).

For general advice on making comparisons with identifiable competitors see Comparisons: Identifiable competitors.

What is meant by verifiable?
What kinds of comparisons require verification information?
What information is needed to make something verifiable?
Where should I provide the information?
What about surveys and test results?
What if my comparison is based on confidential information?

What is meant by verifiable?

The Code does not specify what constitutes ‘verifiable’, but in 2006 the European Court of Justice ruled in the case of Lidl v Colruyt that for a general price comparison to be 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 target audience.

While CAP does not give legal advice, the ASA has taken this position into account when investigating complaints on this issue.

What kinds of comparisons require verification information?

Any comparisons made with identifiable competitors must be verifiable. Marketers do not need to identify explicitly the competitor(s) or product(s) 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 or competitor product, whether or not they are stated in the ad, this will mean that the comparative claims must be verifiable.

If a market is small, highly specialised or dominated by a few major players, the intended competitor(s) are likely to be very clear despite not being named.

Superlative claims are, by their nature, likely to be seen as a comparison with all competitors. Complaints about the claim "#1 World's Live-Games Provider" were upheld by the ASA, because the ads did not direct businesses to any additional information regarding the comparisons (ASTOK Ltd, t/a TVBet, 15 April 2020).  

Some comparisons are easily verifiable; a price comparison between two identical products sold by two different retailers, for example, could be checked by looking on their websites. Other comparisons, such as those that involve many products, are likely to be more difficult to verify, and the ad will need to provide sufficient information to allow consumers to verify the claim.

One advertiser questioned whether their ads were subject to the verifiability requirement, because it did not contain a price comparison and instead referred to its price match scheme. The ASA ruled that because the competitors were identifiable the verifiability requirement applied, and therefore the advertiser should have signposted consumers to their methodology (Wm Morrison Supermarkets plc, 26 August 2015).

What information is needed to make something verifiable?

The information needed to make a comparison verifiable will depend on the specific comparison being made. Generally speaking, marketing communications should include as much information as possible to ensure that consumers are able to check the accuracy of the claim for themselves, and include a signpost in the ad to information about the basis of the comparison. 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.

The information provided must be 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 it did not include, or direct consumers to, objective evidence to support the claim, and was therefore not verifiable (Vodafone Ltd, 28 July 2021).

Sometimes, it may be necessary to provide information about the methodology used, and which competitors or products are being compared. An ad which stated an average customer saving when selling property, based on the fee charged on the advertiser’s average sale price versus the amount if the UK average commission fee of 1.5% had been applied, was found to breach the Code because it didn’t state or provide a signpost to information such as what the average sale price was, how that average (and their associated fee) had been calculated and details of the source for the average estate agent fee (New Broom Ltd, 14 September 2016).

The information must be readily accessible. Providing incomplete information, or information behind a paywall will be insufficient. Although the claim “best dishwasher tablet on test” was supported by evidence to substantiate it, the product test results could only be accessed by consumers who paid for a Which? subscription, so the claim was not verifiable (Procter & Gamble UK, 27 May 2020).

Simply citing a third-party website, such as in the case of price comparisons, without telling consumers which specific products were used in the comparison and the date the comparison was made, is unlikely to be acceptable.

Where a comparison is made with “the leading brand”, although in many cases it is likely that consumers will be able to readily identify the competitor, ads featuring this type of comparison will still need to state or direct consumers to the full information about the comparison, including which products were selected and how the comparison was carried out (Procter & Gamble (Health & Beauty Care) Ltd, 2 December 2015).

Where the data used to support a claim is historic, and therefore cannot be replicated or checked for accuracy, it may be necessary to provide detailed data to make the claims verifiable. The ASA investigated variations of the claim “UK’s NO.1 5G network”, which featured in multiple ads for EE, and considered that the information was not sufficient to verify the claim. Because the test results were historic (ie specific to the six-month period of testing given the continuing roll-out of 5G after the testing period), consumers and competitors would not have been able to replicate the tests, whether or not the detailed testing methodology was made available. The ASA therefore considered that for the claims to be verifiable, the result for each metric at each test location and time would need to made available in an accessible format. Additionally, full particularities about the methodology by which the data was obtained, categorised, assessed, scored and ranked would need to be provided, so that the data could be fully understood and interpreted (EE Ltd, 23 August 2023).

Where should I provide the information?

Marketing communications should be explicit about how readers can verify a comparison. One way of doing so would be to direct consumers to a website that contains information about the basis of the comparison, such as the products, methodology, and results, and make it clear that this is how consumers can verify the claims. Marketing communications could, for example, include “comparison can be verified on www…” or “visit www… to verify the comparison” in small print. Merely including a website or postal address, without stating that it is where consumers can verify the comparison, is unlikely to be sufficient.

A comparison which included claims "Market leading signal strength”, “Fastest speeds in the UK” and “Reaches parts of your home that the best routers from the other big providers can't" was ruled misleading because the means to verify the comparison was not sufficiently or clearly signposted. Although a link to a copy of the test report was provided, it could only be accessed by clicking and expanding a heading found under “Small Print” and clicking through to a page with another link to open the test report (TalkTalk Telecom Ltd, 1 June 2016).

Although an ad which included the claim “the largest breakdown provider” also included the text “more mobile mechanics than any other UK breakdown service” and a footnote which stated the source of the figures, this was not considered sufficient to verify the claim. The ASA considered that, while there was an indication that further information regarding the claim was available, it was not sufficiently clear that this information was the means by which consumers would be able to verify the claim, and the location of the footnote, at the bottom of the page, meant it could have been overlooked (AA Ltd, 20 July 2022).

It is also likely to be acceptable to provide verification information upon request, by directing consumers to contact a postal or email address to obtain verification information (Wm Morrison Supermarkets plc, 26 August 2015).

What about surveys, awards and test results?

Comparisons based on survey results or on the basis of recieving third party awards must include enough information about the survey or award to ensure that the audience can verify the claim. These are likely to need to signpost consumers to information such as the sample size, the methodology, the group of respondents represented in the sample, which competing providers were included and the factors that respondents were required to consider when answering the question(s) on which the claim was based (HPI Ltd, 15 June 2016).

Similarly, efficacy comparisons are likely to need to detail the methodology of the tests carried out, include a breakdown of individual results and make clear which products were tested (Medichem International (Manufacturing) Ltd, 13 April 2016).

Marketers should be aware that self-reported consumer data will not be sufficient to support a claim that would otherwise require objective substantiation. This type of data is unlikely to be sufficient to verify an objective comparison. See Vodafone Ltd, 28 July 2021 and Solvotrin Therapeutics Ltd, 13 June 2018. See Comparisons: Awards and consumer surveys.

What if my comparison is based on confidential information?

The ASA may consider that data should be made available to consumers and competitors when requested, so that they can verify the claim. Marketers are advised against making comparisons if the data cannot be made available to the public because, for example, it is confidential.

A complaint about an ad comparing supplements was upheld because the survey results themselves were not in the public domain and therefore could not be accessed by consumers to allow them to obtain that information themselves (Solvotrin Therapeutics Ltd, 13 June 2018).  

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