Central to many intellectual property disputes is an assessment of the degree of similarity of two contested trade marks. A determination of similarity is generally considered to be a subjective decision, guided primarily by precedents in case law for cases which are deemed to be analogous. However, a more objective framework could have a number of advantages, including the potential to quantitatively measure the difference between marks, define thresholds up to which IP protection could apply, and offering a case-law background where cases could more exactly be compared against each other, providing a basis for greater legal consistency.

A new study by David Barnett considers the cases of colour and word marks, and outlines some potential methodologies for quantifying the degree of similarity of marks. The analysis suggests that it should be possible to construct objective similarity metrics which could be applied to IP disputes and potentially incorporated into case law.

The proposed algorithm for word marks incorporates a number of the desired features of an idealised metric, including a down-weighting of the influence of any final ‘s’, putting greater weight on similarity at the start of the strings, and including elements of ‘normalisation’ relative to the length of the strings – though further ‘tuning’ is likely to be required. It is also worth noting that the current model also takes no account of meaning (i.e. conceptual similarity) and does not attempt to address similarity of associated goods and services classes.

Other future developments might involve efforts to ascertain the likelihood of confusion of marks (rather than just their similarity). One very simple possible basis for this determination – utilising the numbers of results returned by search engines for the marks in question, as a proxy for their overall prominence or genericism – is also discussed in this study.

You can read the full study here.