Ide Kearny and Vincent-Wayne Mitchell Source: Int. Journal of Market Research, Vol. 43, No. 1, 2001 Measuring Consumer Brand Confusion to Comply with Legal Guidelines In actions for trademark infringement and passing off, judges determine subjectively the existence, or likelihood, of marketplace 'confusion'. In arriving at a ruling, a court may rely upon evidence from witnesses, secondary documents (e.g. letters of complaint) and market research, but this is not obligatory. The legal treatment of evidence is coloured by an awareness that many forensic criticisms can be made of the overall standard and effectiveness of structured questionnaire surveys. For example, surveys (1) are frequently badly worded, or poorly executed, (2) prove of no relevance to the action, or produce evidence that helps the other side, and (3) are expensive. The judiciary has expressed a preference for certain types of surveys and set out 'good' market research practice guidelines with which researchers must comply. Here, we examine the problems underlying these criticisms and discuss their market research implications. de Kearney and VincentWayne Mitchell Introduction Imitation can be a very costeffective strategy for manufacturers because it can have the effect of reopening the purchase decision when consumers generalise, or confuse, one brand (or aspects of a brand) with another, and thus may reevaluate existing preferences (Ward et al. 1986). However, brand owners are understandably wary of the potential to (1) lose sales revenue due to mistaken purchases, (2) have their image tarnished by association with a lesser product, and (3) lose exclusivity in an important brand element with the result that they also lose USP. Indeed, there have been a number of recent, wellpublicised trademark disputes involving lookalike products (e.g. United Biscuits 'Penguin' versus Asda's 'Puffin', 1 the Neutrogena/Neutralia dispute, 2 and British Sugar. 3 Surveys suggest that at one time or other anything from 9% 4 to 22% of shoppers have displayed