HC-2013-000089 - [2025] EWHC 2376 (Ch)

Mr Wynn considered there to be evidence that MSD’s infringements enabled MSD to gain website traffic at the expense of Merck, based on an analysis of SEMrush data showing traffic between June and December 2020. He relied specifically on an observation that in the period between June and December 2020, the SEMrush data showed an increase in Merck’s web traffic and a corresponding fall in MSD’s web traffic. Mr Wynn noted that the final order of Sir Alastair Norris was handed down on 28 July 2020. He considered that the shift in Merck’s and MSD’s website traffic likely resulted at least in part from changes made to MSD’s websites to comply with the July 2020 order. He quantified the benefit to MSD from increased web traffic as £1.6m.

The problem with Mr Wynn’s analysis arose from the evidence in the witness statement of Merck’s own witness, Mr Sielaff, regarding the use of SEMrush data. Mr Sielaff explained that SEMrush data provides an estimation of web traffic based on the search volume of a keyword and the site’s position in search results. He noted, however, that “web traffic data presented by SEMrush has a three-to-six month delay between an event occurring (like a change of content on the website) and the results of that event being visible in the SEMrush data. This is due to gradual shifts in Google keyword ranking data”.

On close analysis, the SEMrush data showed the most dramatic symmetrical movement in the website traffic between June–July 2020, with very little symmetrical movement from August 2020 onwards. Once the time lag of three to six months is factored in, the July 2020 order could not have been the cause of the significant shift in Merck’s and MSD’s website traffic in the SEMrush data for June to July 2020, or even the less pronounced traffic movements between July and August 2020.

Mr Wynn had reviewed Mr Sielaff’s evidence as to the time lag in the SEMrush data, and said that this was the basis on which he selected the period from June to December 2020. That would have been a reasonable approach if the SEMrush data showed a symmetrical shift in website traffic occurring gradually between October and December 2020, or even between July and December 2020 (on the basis that, as Mr Brandreth said, it does not follow from Mr Sielaff’s explanation that the July 2020 order would have had no impact at all on the SEMrush data until three months later). That does not, however, account for the fact that the main traffic shift identified in Mr Wynn’s chosen period occurred before the final order had even been handed down, so could not possibly have been caused by steps taken by MSD to implement the final order.

When cross-examined on this point by Mr Hollingworth, Mr Wynn accepted that if the flaw identified in his analysis was correct, then his figures of traffic lost and gained could not stand. He also agreed that he had not done any other analysis to try to isolate the effect of any traffic gain by MSD at the expense of Merck. For the reasons given above, I consider that Mr Wynn’s analysis was indeed flawed, and cannot be regarded as providing reliable evidence of any traffic shift from Merck to MSD. Mr Brandreth rightly pointed out that Dr Stec had not identified this particular problem with Mr Wynn’s analysis. But the problem arose inexorably from a closer scrutiny of the precise data on which Mr Wynn relied, and the Merck evidence on which Mr Wynn also specifically relied.

Turning to Dr Stec’s evidence, his view was that (for different reasons) there was no reliable evidence of a causal link between the July 2020 order and the pattern of the data traffic. He considered that when viewed over a longer period, the SEMrush data did not show any overall decrease in Merck’s traffic data that could be correlated to action by MSD. He also noted that using Google Analytics data presented a materially different traffic pattern over the same period. Ultimately, he said that there were many confounding factors at play in the data, and that Mr Wynn’s analysis had not controlled for the effect of those different factors.

It is not necessary to explore Dr Stec’s comments in this regard in any detail, given the fatal problem with Mr Wynn’s evidence discussed above. It is sufficient to say that in the absence of Mr Wynn’s analysis, there was no evidence before the court of any diversion of website traffic that could support the inclusion of this factor in the economic benefits analysis.