The “strength” of patent systems
Stronger does not necessarily mean better
As discussed in a previous post, patent “quality” has many facets. One is compliance with statutory requirements. Do patent offices grant and refuse applications in line with their own rules, or do they make mistakes? Under this lens, a “low-quality” patent is one unlikely to survive a court challenge. But perfect compliance is not the whole story. A patent system could have a bar so low that the office issues patents on every trivial invention. The office would never make a “mistake,” yet such a low threshold is hardly a mark of true quality.
That discussion brings us to a second, equally important dimension: rigor. How high is the bar? Are patents awarded only for genuine advances—novel, non-obvious contributions—or is the threshold so low that almost anything under the sun qualifies as “inventive”? To capture these differences, scholars have devised indices measuring the strength of patent systems. This post reviews some of the major indices and explores what they reveal about international variation in patent systems.
Ginarte and Park’s index
The Ginarte and Park index was first released in 1997 and remains the most widely used measure of patent-system strength. Drawing on the formal laws “on the books,” it assigns each country a composite score based on five legislative and institutional dimensions:
Coverage. Assesses which categories of inventions are eligible for patent protection (e.g., pharmaceuticals, chemicals, plant varieties, software, etc.). Fewer exclusions imply a more expansive (“stronger”) system.
Membership in international treaties. Awards points for participation in key agreements such as the Paris Convention, the Patent Cooperation Treaty, and the International Convention for the Protection of New Varieties of Plants. Treaty obligations typically raise minimum standards and promote harmonization.
Duration of protection. Measures the statutory patent term. The international norm of 20 years from filing serves as the benchmark; shorter terms reduce a country’s score.
Enforcement mechanisms. Captures whether national law provides tools for patent holders to defend their rights, such as preliminary injunctions, contributory‐infringement claims, reversals of the burden of proof, and similar remedies.
Restrictions on patent rights. Penalizes systems that impose compulsory licensing, domestic‐working requirements, or other legal limits that weaken patent exclusivity.
By summing the scores across these five categories, the Ginarte and Park index delivers a single number reflecting each country’s formal patent-law strength. Higher scores indicate more robust regimes—that is, systems with broader coverage, stronger enforcement, and fewer built-in limitations. This index is widely employed in economic research to examine how variations in patent-law strength affect indicators such as innovation, trade flows, and foreign direct investment (FDI).
Yet, despite its broad adoption, scholars have identified notable limitations of the Ginarte and Park index. First, as a general measure, it may obscure sector-specific features of patent regimes. This issue prompted the creation of targeted indices, such as those for pharmaceuticals and plant varieties. Second, by relying solely on “law on the books,” it overlooks the real-world effectiveness of those laws—what scholars call “law in practice.” Third, because it focuses on the generosity of formal rules and remedies, calling high scores “strong” can be misleading: these values often reflect applicant friendliness more than patent system robustness. In the sections that follow, we explore the challenges of measuring enforcement in practice and consider alternative approaches to assessing patent quality.
Law in practice
The Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS), administered by the World Trade Organization (WTO), entered into force on January 1, 1995. It is the most comprehensive multilateral treaty on intellectual property (IP), setting minimum standards for the availability, scope, and use of IP rights. TRIPS spurred rapid convergence in “law on the books” across WTO members, but significant disparities remain in enforcement and administration. Patent owners’ real ability to exercise their rights depends not only on statutory rules but on how those rules are applied in practice. Hence, the need for a complementary perspective: law in practice, which captures the effectiveness of IP-law enforcement by courts, police, customs authorities, and other institutions.
Because “law in practice” involves diffuse enforcement routines, nuanced procedural norms, and informal institutional behaviors that resist simple codification, it is far harder to measure than “law on the books.” Direct data on enforcement outcomes—such as court filings, injunctions granted, or damages awarded—are often unavailable or incomplete. Even where records exist, compiling comparable indicators of judicial independence, administrative efficiency, or enforcement-official competence across dozens of countries is no small feat. Layered on top of this are culture-bound conventions and unwritten protocols—how judges, prosecutors, and customs officers actually interpret and apply statutes day to day—which defy straightforward quantification.
Despite these challenges, researchers have devised several proxies for “law in practice.” Political scientist Robert Ostergard, for example, incorporated enforcement evidence drawn from the U.S. State Department’s Country Reports on Economic and Trade Practices. Economist Beata Javorcik used assessments from the International Intellectual Property Alliance’s Special 301 recommendations. Management scholar Nick Papageorgiadis and colleagues offer perhaps the most comprehensive analysis, with an index that quantifies enforcement based on three categories of transaction costs faced by rights holders:
Servicing costs. Quality of patent administration.
Property-rights protection costs. Judicial efficiency, corruption, and related factors that affect court-based enforcement.
Monitoring costs. Resources required to detect infringement, including police engagement and public commitment to IP protection.
“Strength,” or applicant-friendliness?
The indices we have reviewed so far capture the strength of patent laws and enforcement, but they don’t tell us whether the patents actually granted would survive a court challenge. In other words, they measure how generous or friendly a system is to patent owners, not how robust its patents are.
Recognizing this limitation, economist Bruno van Pottelsberghe produced a series of studies aimed at measuring the quality of patent systems. He developed a “quality index” built around nine operational design features. Seven of these relate to procedural safeguards—such as the window for requesting examination, the availability of post-grant opposition, and grace-period length—while two indicators capture patent office resourcing: personnel expenses per staff member and the average number of claims examined per examiner.
Building on this procedural focus, he also exploited procedural data published by patent offices, seeking to convert them into quantifiable examiner-centred metrics, including search completeness through classification and citation practices, the upfront certainty of information delivery, the speed of information delivery, and the relative stringency assessed via grant rates. This research line admittedly offers a more direct gauge of patent strength. However, it does not tell us how high or low the bar is for patent applications to be granted.
Insights from “twin patent” studies
A complementary approach to gauging patent‐system rigor uses twin patents—matched filings for the same invention made at different offices—and compares grant outcomes across jurisdictions. A team of Australian economists, for example, examined triadic patent applications (filed in the United States, Japan, and Europe) and documented significant “disharmony”: decisions on the same invention often diverge, with some offices granting patents that others reject.
Such inconsistencies are not inherently problematic, for different countries may legitimately apply distinct patentability standards. However, they can also signal examiner errors. In a follow-up study, Gaétan de Rassenfosse and colleagues decompose these discrepancies into two sources: variation in patentability thresholds and outright mistakes. Analyzing data from the five largest offices (the triadic offices plus China and South Korea), they find that systemic differences in examination standards explain most disharmony, while true errors play a more limited role.
Crucially, their model also quantifies each office’s effective “bar height.” They show that the JPO applies the strictest standard, followed by the EPO, the KIPO, the USPTO, and finally CNIPA—clearly documenting differences in patent offices’ rigor.
What explains cross-country differences in patent protection?
Recognizing the vast differences in the level of patent protection across countries, scholars have sought to understand the factors that explain these variations. They find that countries tend to calibrate their IP regimes dynamically as they develop. At early stages of industrialization, when domestic firms lack significant innovative capacity, patent systems are often weak or narrow. Weak systems allow local actors to imitate established technologies without stringent legal barriers. As a nation’s technological base and R&D capabilities grow, however, pressure mounts to strengthen IP rights, both to reward nascent innovators and to secure access to foreign markets. China exemplifies this trajectory: its patent laws and enforcement apparatus have been progressively tightened over the last three decades, in tandem with the rise of home-grown “national champions” that compete globally and demand robust protection at home.
However, whether weak IP regimes truly benefit developing economies remains a topic of hot debate. Critics of lax IP argue that multinational firms will hesitate to establish R&D centers or high-value manufacturing in countries where their core technologies can be pirated. Empirical studies have found that stronger patent protection is correlated with greater inflows of technology-intensive FDI, suggesting that weak regimes can deter knowledge transfer and thereby limit learning-by-doing opportunities.
However, proponents of early-stage flexibility counter that imitation is a key engine of catch-up. By allowing domestic firms to reverse-engineer and adapt foreign innovations, weak IP rights can accelerate capability building, foster competitive industries, and lower entry barriers.
Ultimately, the political economy of IP reform—shaped by domestic interest groups, trade negotiations, and institutional capacity—determines each country’s unique path along this dynamic spectrum.
Please cite this post as follows:
de Rassenfosse, G. (2025). The strength of patent systems. The Patentist Living Literature Review 5: 1–5. DOI: 10.48550/arXiv.2505.07121.