Comparative advertising can be a great way to make your company stand out in the marketplace and can also help consumers decide which product or service is best for them. But it can be an area that generates complaints, both from your competitors and members of the public, so it’s important to know what the rules are.

Here are four key things to think about before running a comparative ad:

What claim do you want to make?

Think carefully about the claim you want to make and how it will be understood by consumers – if the claim is ambiguous then you risk being misleading so make sure it’s clear. A teachers’ union making the claim to be the “largest teachers' union in the UK" intended the claim to be a reference to currently practising teachers only, but the ASA said this wasn’t obvious to readers and that this should have been made clear in the ad itself.

Unless it is obviously puffery, the ASA is likely to regard superiority claims as objective. Depending on the context, describing your product as the “best” with no other reference to the criteria is likely to be regarded as subjective. However, the ASA has previously upheld “best” claims where it considered that in the context they would be understood as objective. A website for a private healthcare clinic included claims that their consultants were “the best in Europe”, which the ASA said was likely to be interpreted by readers as a claim that their consultants had been objectively shown to be better than their peers.

When making an objective claim you should, as always, make sure you hold documentary evidence to support it before running the ad.

Is it a comparison with an identifiable competitor?

If your ad refers to an identifiable competitor then specific rules apply (CAP Code rules 3.33 – 3.37). This applies to ads which in any way, either explicitly or by implication, identify a competitor or a product offered by a competitor – so not just to ads where you name a competitor. Ads don’t even have to include a specific comparison as it would generally be understood to fall under these rules. For example a supermarket ad which included the claim "You won't lose out on big brands, own-label or fresh food" and referred to competitors with whom the price-match scheme compared prices was considered by the ASA under these rules.

Are you comparing products meeting the same need or intended for the same purpose?

Comparisons with identifiable competitors must compare products meeting the same need or intended for the same purpose (CAP Code rule 3.34). Essentially, the products being compared must display a sufficient degree of interchangeability for consumers. Examples of products it would likely be acceptable to compare under this rule include: branded and non-branded beans; beer and wine; or organic and non-organic produce. However, you still need to ensure the basis for the claim is made clear and that the ad isn’t likely to mislead.

Is the comparison verifiable?

Comparisons with identifiable competitors must objectively compare one or more material, relevant, verifiable and representative feature of those products, which may include price (CAP Code rule 3.35). For the comparison to be considered verifiable you must give readers enough information to understand it and include a signpost in the ad to that information. If checking that information requires special knowledge most consumers are unlikely to have, readers should be able to get a knowledgeable and independent person or organisation to verify the comparison.

Some claims (such as a price comparison between two products) might easily be checked by consumers for themselves and so no additional verification information would be required. However, for more complex claims such as a basket of goods comparison or claims based on product testing, you should ensure the ad clearly states how the comparison can be verified. This could be done by stating “[the claim] can be verified at” or by inviting readers to write to a postal address in the ad. Marketers wanting to make a comparison based on commercially sensitive data should consider this requirement carefully because the ASA may uphold complaints if you do not make sufficient information available to consumers and competitors for them to verify the claim.

You should also make sure that the verification information is sufficient for readers to understand and verify the claim. The ASA upheld complaints in a case where verification information was provided to consumers but was not clearly signposted in the ad, included a number of errors and inconsistencies and did not contain sufficient information about how the comparison had been made.

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