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

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

Mine Güner discusses bridging law and business, taking the initiative, and why Taylor Swift helped put copyright on the map
Cindy Goh discusses why she launched Cheang & Ariff's IP department, the improving litigation environment in Malaysia and what to consider when using AI
Increased focus on adding patent litigation depth to the firm’s Dallas office was behind the boutique’s most recent hires
IPH's Canadian acquisitions are paying off on paper, but a couple of strong years may not be enough to show that the group's strategy has truly won over the market
Examiner statistics could help patent prosecution practitioners tailor strategies, turning an area of high variability into a potential competitive advantage
The England and Wales High Court’s ruling in Accord v Novartis may not rewrite the law on plausibility, but it does signal a pragmatic approach that could provide greater certainty for life sciences innovators
Firms with established sports relationships and specialised expertise are well positioned to capture the market’s expanded pool of IP work
Gunjan Paharia discusses developing RIA, an AI platform built to draw on decades of institutional knowledge, support junior lawyers, and reshape how legal teams work
A strong Canadian business helped lift profits, but the IP service group's latest results underline the pressure facing its operations in Australia, New Zealand and parts of Asia
Wins in court have been key to the six-year-old firm’s growth, as one of its founders explains
Gift this article