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.


A ‘basket of goods’ comparison involves a retailer comparing a number of items that a consumer might buy in a shopping visit to their store against a similar basket of goods bought at a rival store. The ASA has considered that a shopping basket survey, which would always be restricted to a selection of products, is a valid means of comparing the price performance of retailers.

Make fair and representative comparisons
Make the basis of the comparison clear
Hold evidence
Make the claim verifiable

Make fair and representative comparisons

Marketers comparing shopping baskets should compare a fair and truly representative selection of goods and not skew the comparison to give themselves an artificial advantage, for example, by including an untypically high number of high-priced products that were substantially cheaper than their competitors' equivalents.

The products in a basket should be products typically bought by shoppers in a combination that reflects customers' normal shopping habits.

Advertisers are entitled to compare un-branded or own brand products with branded products, provided this is clear in the ad and the comparison is fair and representative. An ad should not compare an unrepresentative number of higher priced branded products with their own in order to claim an unrepresentative price advantage.  In 2016, the ASA upheld a complaint about an ad that claimed customers could save on a big weekly shop. In each of the three comparator shops the processed and non-fresh products were branded products, and only the fresh products were own-brand, along with a small number of other products. Because the ASA had not been provided with any evidence from the advertiser that the comparison included a fair and truly representative selection of goods typically purchased, and because they considered that it was unlikely that price conscious consumers to whom the ads were targeted would purchase such a large proportion of branded goods when own-brand goods were typically cheaper and available, the comparison was considered misleading (Aldi Ltd 29 June 2016).

Make the basis of the comparison clear

A shopping basket featuring some own-brand goods may be compared with a basket containing only branded goods as long as the ad makes this clear.  Two ads which featured four individuals and stated that they had saved against their usual weekly shops with Aldi were considered misleading, because they did not make the basis of the comparison clear. The ads included small text which stated "84 out of 98 people saved”, and the ASA considered that consumers would therefore understand that 98 people had participated in the eight-week challenge, when in fact only four people had (Aldi Stores Ltd 31 December 2014).

The ASA has criticised many marketers for not making clear that they have used promotional prices in their comparison (Boots UK Ltd, 22 October 2008). The ASA considered that one marketer’s footnote “Includes Tesco products on promotion”, did not negate the misleading impression given by the headline (Tesco Stores Ltd, 20 August 2008).

Savings claims such as ''We're cheaper than Y'', “Why pay more at Y” or similar, can imply that the marketer’s prices are on average lower than their competitors across their product range; marketers should take care to ensure that such claims are supported by comprehensive comparative evidence or that the meaning of their claim is stated clearly (Tesco Stores Ltd, 20 August 2008 and ASDA Stores Ltd, 14 March 2007).

Ads should make it clear if the comparison is made with specific competitors, and should not make any claims which could be interpreted as an absolute comparison against the whole market, e.g., “we have the cheapest prices”. An ad for Tesco which compared the price of a Christmas shop at 5 supermarkets was considered misleading because, whilst the qualifying text in the ad stated which supermarkets were included in the comparison, the headline claim stated “no one is cheaper for your big Christmas shop”, which was likely to be considered an absolute comparison with the entire market (Tesco Stores Ltd, 21 May 2014).  

Unless they operate a national pricing policy and prices are the same for everyone irrespective of local or regional competitor activity, marketers should state where and when surveys featured in their marketing communications were carried out (ASDA Stores Ltd, 14 January 2009).

Hold evidence

As with all comparative claims, marketers must hold evidence to demonstrate that their claims are accurate.

When making a price comparison, marketers should take account of their competitors’ pricing policy (especially their response to price-led advertising), the speed with which changes in price are likely to occur and the shelf-life of the media they choose to use. Marketers should not state or imply that prices, and therefore savings, are valid for longer than they are.

Make the claim verifiable

Comparisons with named or identifiable competitors should be verifiable. In order for a comparison to be verifiable, ads should state or signpost to the data on which the comparison is based so that readers of the ad can verify the comparison. A complaint against an ad for the Morrisons price match scheme was upheld because the ad did not include sufficient information to verify the comparison, and should have included a signpost to the methodology which would enable consumers to ascertain readily the basis on which Morrisons made their comparison. In this case the 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, however the ASA ruled that because the competitors were identifiable the verifiability requirement applied (Wm Morrison Supermarkets plc t/a Morrisons, 26 August 2015).

See Comparisons: General,  Comparisons: Verifiability and Pricing: General.


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