Explainer · Plain-language

What is the Leiden Manifesto for research metrics?

The Leiden Manifesto for research metrics is a set of ten principles for the responsible use of quantitative indicators in research evaluation, published as a comment in Nature in April 2015. Written by Diana Hicks, Paul Wouters, Ludo Waltman, Sarah de Rijcke, and Ismael Rafols, it argues that metrics should support — not replace — expert judgement, and that indicators must be tailored to the discipline, institution, and purpose of the evaluation.

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The short answer

The Leiden Manifesto responds to a growing concern that research evaluation had become over-reliant on bibliometric indicators such as the journal impact factor and h-index, often applied without regard for context. Its ten principles call for quantitative metrics to complement qualitative expert assessment; for performance to be measured against an institution's own stated mission; for locally relevant research to be protected; for data and analysis to be transparent; for those being evaluated to be able to verify the data used about them; for field-specific variation in citation practices to be respected; for individual researchers to be assessed on the basis of a qualitative judgement of their portfolio; for false precision to be avoided; for evaluators to recognise that metrics reshape the behaviour they measure; and for indicators to be regularly reviewed and updated.

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Background and origin

The Leiden Manifesto was drafted at the 19th International Conference on Science and Technology Indicators, held in Leiden in September 2014, and published in Nature (volume 520, pages 429–431) on 22 April 2015. Its authors — Diana Hicks (Georgia Tech), Paul Wouters (Leiden University), Ludo Waltman (Leiden University), Sarah de Rijcke (Leiden University), and Ismael Rafols (Brunel University London / Ingenio CSIC-UPV) — represent expertise in public policy, scientometrics, and research evaluation. The manifesto emerged from a widespread sense that the institutional uptake of bibliometrics had outrun the methodological sophistication with which indicators were being applied. The specific trigger was the global spread of university ranking systems and national evaluation exercises that reduced complex scholarly output to single-number scores, rewarding publications in high-impact journals regardless of their field relevance or scientific rigour. The manifesto is available in its original form at leidenmanifesto.org and has been translated into more than a dozen languages.

The ten principles in practice

The ten principles of the Leiden Manifesto are actionable rather than aspirational. Principle 1 asserts that quantitative evaluation must support — not supplant — qualitative expert assessment. Principle 2 requires that performance be measured against the stated research missions of the institution or group, not against a generic external benchmark. Principle 3 calls for protection of locally or nationally relevant research that may not appear in international citation databases. Principles 4 and 5 address transparency: data collection and analysis should be open and simple, and those being evaluated must be able to verify the data used about them. Principle 6 requires that evaluators account for field-specific differences in citation rates and publication practices — a paper in mathematics or the social sciences cannot fairly be assessed using impact thresholds calibrated on biomedical journals. Principle 7 insists that individual researchers be assessed qualitatively, on their full portfolio of contributions, not reduced to a single metric. Principle 8 warns against misplaced concreteness and false precision — a mean citation score expressed to two decimal places implies an accuracy that the underlying data does not support. Principle 9 recognises that metrics have systemic effects: if citation counts drive career advancement, researchers will adapt their behaviour accordingly. Principle 10 calls for regular scrutiny and updating of indicators as circumstances change.

Relationship to DORA and CoARA

The Leiden Manifesto is one of three widely cited frameworks for responsible research evaluation, alongside the San Francisco Declaration on Research Assessment (DORA, 2012) and the Coalition for Advancing Research Assessment (CoARA, 2022). DORA focuses specifically on eliminating the use of journal-level metrics such as the impact factor in hiring, promotion, and funding decisions. The Leiden Manifesto is broader in scope: it does not call for the elimination of metrics but for their informed and contextualised use. CoARA, which builds on both DORA and the Leiden Manifesto, establishes a set of commitments for signatories — universities, funders, and research organisations — to reform evaluation practices across Europe and internationally. Together, the three frameworks reinforce each other: DORA challenges specific misuses of metrics, the Leiden Manifesto provides positive principles for good practice, and CoARA provides a governance structure for institutional reform.

Adoption and influence

In the decade since its publication, the Leiden Manifesto has been cited in national research evaluation policy documents across Europe, Asia, and Latin America. The Dutch Research Council (NWO) and the Dutch universities adopted a recognition and rewards strategy in 2019 — Erkennen en Waarderen — that draws directly on Leiden Manifesto principles, particularly around qualitative portfolio assessment and the protection of diverse research activities including education, leadership, and knowledge exchange. The European University Association has referenced the manifesto in its guidance on responsible evaluation. In the UK, Research England's guidance on the Research Excellence Framework (REF) has progressively moved away from journal-level metric proxies, consistent with Leiden Manifesto principles. The manifesto's lasting contribution is to have framed responsible use of metrics as a matter of principle rather than mere technical preference.

Key facts

At a glance

Published: Nature, 22 April 2015, volume 520, pages 429–431
Authors: Diana Hicks, Paul Wouters, Ludo Waltman, Sarah de Rijcke, Ismael Rafols
Principles: 10, covering qualitative primacy, mission alignment, transparency, field variation, and systemic effects
Website: leidenmanifesto.org (original text; translations into 12+ languages)
Relationship to DORA: Complementary — DORA targets specific misuses; Leiden provides broader positive principles
Influence: Cited in Dutch Erkennen en Waarderen strategy, EUA guidance, and research council policy frameworks

Common misconceptions

What people often get wrong

Often heard: The Leiden Manifesto calls for abandoning bibliometrics altogether.

Actually: The manifesto argues for the responsible use of metrics, not their elimination. Principle 1 explicitly positions quantitative evaluation as a support for qualitative expert assessment, not a replacement for it.

Often heard: The Leiden Manifesto and DORA say the same thing.

Actually: DORA focuses specifically on ending the use of journal-level metrics such as the impact factor in individual assessments. The Leiden Manifesto is broader: its ten principles cover transparency, field variation, mission alignment, and systemic effects beyond any single indicator.

Often heard: The Leiden Manifesto only applies to university research evaluation.

Actually: The manifesto explicitly addresses evaluation at the level of institutions, research groups, and individual researchers, and is relevant to funders, government agencies, and any body that uses bibliometric data to inform research policy.

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