Expert witnesses in patent litigation around the world

Managing IP is part of Legal Benchmarking Limited, 1-2 Paris Gardens, London, SE1 8ND

Copyright © Legal Benchmarking Limited and its affiliated companies 2026

Accessibility | Terms of Use | Privacy Policy | Modern Slavery Statement

Cookies Settings

Expert witnesses in patent litigation around the world

geek.jpg

Expert witnesses can be decisive in the outcome of patent cases, but rules on their use vary widely. We invited correspondents in Germany, Japan, the UK and US to discuss procedures and practical tips

geek.jpg

With so much IP litigation today being international, and involving an element of forum-shopping, parties have to weigh up many considerations when deciding where and when to bring an action, or how to defend it.

Some of these questions are purely legal: What rights do we have? Do we have standing? What actions are permitted in a particular jurisdiction? But many questions are also strategic: How long will a case take? What will it cost? How will it be decided? What evidence can be brought? Often, these strategic questions are decisive for the outcome of the dispute.

In patent litigation in particular, the role played by expert witnesses can be vital, especially in cases where the technology is complex and judgements about validity and infringement can be finely balanced. And yet the rules on the use of experts vary greatly between different jurisdictions.

Germany, Japan, UK and US compared

In a special feature published this month, we invited correspondents in Germany, Japan, the UK and US to describe how expert witnesses are used in litigation in those four jurisdictions, and also how parties can make the most of expert witnesses.

In Germany, courts recognise both court-appointed experts and party experts – though in practice they are only used in a tiny number of cases. Courts place tight restrictions on the use of court-appointed experts, while party experts may be of limited value and may even do more harm than good.

Japan also has different types of experts, and the role of judicial research officials and technical advisers is especially important in patent cases. Technical advisers in particular are now an accepted and well understood part of litigation in the country.

In the UK courts, experts play a vital role and can even be instrumental in the outcome of a case. Selecting the right expert and carefully instructing them is therefore a crucial part of litigation strategy. What is required of experts has been elucidated in a number of cases over the years and it is also important to consider personality issues: how credible will your expert be before a judge, particularly in cross-examination?

Similarly, in US litigation both consulting and testifying experts provide the court with invaluable assistance that may be case determinative (and a strong expert report may lead to pre-trial settlement). The standards expected of experts have been clarified in federal rules and case law and, as in the UK, the ability to select and prepare your expert is a key skill for litigators.

Comments welcome

We selected these four countries as they are among the most important in patent litigation globally; we may cover other countries in future issues if readers are interested, so please do let us know via the comments.

more from across site and SHARED ros bottom lb

More from across our site

From cross-border jurisdiction to the end of the transitional period, Powell Gilbert’s Ioana Sabau and Bryce Matthewson predict the biggest talking points ahead
A wave of office launches and lateral hires reflect the draw of patent disputes, but booming AI, semiconductor and data centre markets are offering an even bigger IP opportunity
The hire of Frederick Nicolle as a partner continues Pinsent Masons' expansion while reducing Simmons’ patent prosecution offering in London to zero
The expansion into Granada forms part of a national ‘decentralisation’ strategy focused on providing proximity to research and tech businesses away from traditional hubs
Three successive wins have got the firm eyeing additional opportunities as ITC work booms
While many firms remain focused on generative AI, recent hires and practice launches suggest the next battle may be for lawyers who understand how AI is moving into the physical world
The explosion of data centres has prompted patent pool operators to create new licensing opportunities
The court struck out copyright claims brought by Ladbrokes owner Entain, saying that ownership details should have been completed before litigation began
Düsseldorf has overtaken Munich as the UPC's busiest division, while firms including Winston Taylor, Clifford Chance, and Hoyng Rokh Monegier featured in disputes involving Abbott, Essity, Amazon and Hurom
The managing partner gave up an equity partnership track in New York to build a practice in India. More than a decade later, she discusses entrepreneurship, leadership, and why women should not wait before taking the next step
Gift this article