We aim to provide complete and accurate search reports and written opinions in a consistent, harmonised manner so you can make the right decisions about your patent application.

Complete and accurate searches and written opinions

Our examiners have access to the largest database of prior art in the world, with billions of technical records dating back to 1782. Our collection is constantly growing and helps us deliver a comprehensive search of the highest quality.

The world’s largest prior art collection

  • Patent documents from 106 countries
  • 82 million patent families - 146 million publications
  • Complete collections from Japan, China and Korea (57 million patent families representing 73 million publications, all available in English full text)
  • 114 million non-patent literature groups in-house, combining technical publications and abstracts
  • Access to 10 000 academic and technical journals
  • 4.6 million standards documents (including drafts)
  • 444 000 traditional knowledge documents
  • 13 900 Community Plant Variety Office documents

In 2022, the EPO cited Asian-origin prior art in 48.2% of its search reports.

Graph showing the percentage of search reports with an Asian citation growing to 48.2% in 2022
Figure: Asian prior art in EPO search reports 

28.7% of EPO search reports contained at least one non-patent literature (NPL) citation in 2022, up from 27.8% in 2021.

4.8% of EPO search reports contained at least one standards document in 2022, up from 4.4% in 2021.

Bar chart showing that in 2022 4.8% of search reports contained one or more standards citation, up from 2.9% in 2018
Figure: Percentage of EPO search reports with one or more standards citations

Collaborative Patent Classification

The EPO uses the Cooperative Patent Classification (CPC) scheme, the world's leading standard classification system, which celebrates its tenth anniversary in 2023.

  • Currently used by 38 offices
  • Independent of language, enabling EPO examiners to find relevant prior art in Asian languages, for example

Independent quality audits

Our Directorate Quality Audit (DQA) extended its search audit in 2021, as a way of gaining more in-depth insights into the quality of our searches and written opinions. As expected, refining the audit criteria to include five additional criteria focused on written opinions caused a decrease in the percentage of files with no findings from an all-time high of 96.6% in 2021 (excluding written opinions) to a stable 82.6% (±2.5%) at the end of 2022.

The impact of the extended search audit on the 2022 results can be seen clearly, with findings mainly relating to quality improvements in the written opinion and representing 9.7% of audited files. This is providing us with more information to improve this flagship product. Findings relating to clarity are also included under quality improvements.

Bar chart showing the number of files with findings in the 2021 and 2022 audits with the number with no findings lower in 2022 (82.6%) due to revised audit criteria
Figure: Search: quality audit findings 

A consistent and predictable approach  

We consistently perform thorough searches and cite high volumes of relevant prior art helping our applicants make informed and timely decisions. In 2022, 84.5% of EPO search reports identified at least one document that was prejudicial to the novelty or inventive step of one or more of the application's claims. Our search reports have remained remarkably consistent in citing these large volumes of relevant citations over the years.

Chart: Searches with at least one relevant citation and searches with only A-category citations between 2015 and 2022
Figure: Searches with at least one relevant citation and searches with only A-category citations 
Negative search opinion rate: ratio of positive search opinions to all EP (incl. E-PCTbis) and PCT Ch. I search opinions that year.

We consistently provide thorough written opinions: 93.2% of written opinions raised at least one objection in 2022.

Bar chart showing an increase in negative search opinions between 2013 and 2022, with the rate growing to 93.2% in 2022
Figure: Negative search opinions

Delivering complete searches and written opinions on time

Timeliness is important to our users: 95% of searches and written opinions were dispatched within 8.6 months, the mean average being 4.9 months.

Line graph showing the median, mean and p95 lines for search timeliness from 2016 to 2022. 95% of searches and written opinions were dispatched within 8.6 months, the mean average being 4.9 months
Figure: Search timeliness 2016-2022

User satisfaction survey

Our regular independent user satisfaction survey shows high levels of satisfaction with our search products. In our 2022/2023 survey, 80% of respondents were satisfied or very satisfied with the EPO's performance in this area.

Breakdown of answers in the User Satisfaction Survey showing (very) good ratings were high in most categories
Figure: User satisfaction survey results for search and written opinions
- SR stands for search report, WO means written opinion.
- Arrows indicate statistically significant changes.
- The results of the USS 2022/2023 have been available since May 2023 and will form the basis for 2023 quality improvement actions.