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 comparative advertisements 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).

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?

It is clear from the ECJ judgment that the requirement for verifiability is not confined to price comparisons and the ASA has ruled that it would also apply to general comparisons.

An ad which compared the number of people likely to be affected by noise at two proposed runways but did not include any information regarding the source of the figures was ruled against because the claims were not verifiable (Gatwick Airport Ltd, 12th August 2015). Similarly an ad for an optician that claimed they achieved “better results than anyone else in Europe” was considered problematic, as a means for consumers to verify the claim was not provided (Optical Express Ltd, 8 September 2010).

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

Marketers should be aware that competitors do not need to be explicitly named in an ad for them to be identifiable. Whether a competitor or its products are identifiable will obviously depend on the ad, claims, audience, context and nature of the market in which the advertiser operates. “Leading” claims are, by their nature, likely to be seen as a comparison with all competitors as are claims like “UK’s most effective…” (Medichem International (Manufacturing) Ltd, 13 April 2016;, 27 May 2015).

How can I make sure my comparisons are verifiable?

Advertisers should give readers enough information about the comparison to understand it and include a signpost in the ad to information on 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.

Some comparisons are easily verifiable; a comparison between two identical products sold by two different retailers, for example, could be checked by looking on their websites. But some comparisons, such as those that involve many products, could be more difficult.

An ad that contained a comparison of that type was ruled to breach the Code because, although the comparison was unlikely to mislead, it gave no way for readers to verify the advertised savings (ASDA Stores Ltd, 14 January 2009). Similarly an ad for kitchens that provided only enough information to verify some aspects of the products being compared and their respective prices, was judged not to be verifiable and in breach of the Code (Wren Kitchens Ltd, 30 January 2013).

How can I provide the information?

Perhaps the most straightforward way to ensure a comparison is verifiable is to direct consumers to a website that contains information on the basis of the comparison, such as the products, prices and the methodology. Marketers could, for example, include “comparison can be verified on www…” or “visit www… to verify the comparison” in small print.

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 t/s Morrisons, 26 August 2015).

Simply citing a third-party website, such as in the case of grocery retailer 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.

How do I make signposts clear?

Marketers should be explicit about how readers can verify a comparison; 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 about "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 considered not to have been 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).

What constitutes ‘relevant information’?

In terms of the information required to make a comparison verifiable, this will depend entirely on the specific comparison and the evidence used to support it. Generally speaking, marketers should include as much information as possible to ensure that consumers are able to check it for themselves.

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).

Similarly, the claim "you save up to 90%" against 'banks' was ruled misleading because the ad did not contain or signpost to details about the basis of the comparison, such as the identity of the competitors, the currency transfer routes compared and the currency amounts compared in the mystery shopping exercise (TransferWise Ltd, 4 May 2016).

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).

What about surveys and test results?

Comparisons based on survey results, particularly where the details are not published or accessible in the public domain, 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 (TalkTalk Telecom Ltd, 1 June 2016; Medichem International (Manufacturing) Ltd, 13 April 2016).

What if my comparison is based on confidential information?

Comparisons based on commercially sensitive or confidential data should be made with care since in the case of some comparisons the ASA may decide that such information should be made available to consumers and competitors when requested.

See also, 'Comparisons: General'.

Updated 5 December 2016


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