Institutions function through rules. Rules determine who may become a member, who may use collective resources, how decisions are taken, how conflicts are resolved, how cooperation is organised and how agreements are enforced. They constitute the formal governance architecture through which institutions operate.

Much institutional research focuses on organisations as a whole. The Common Rules Database instead focuses on the rules that make those organisations function. This allows researchers to compare governance at a much finer level of detail and to ask questions such as:

• How do different institutions regulate similar collective action problems?
• Which types of governance rules recur across different institutional settings?
• How do institutions differ in their approaches to membership, resource management, monitoring or sanctioning?
• Which combinations of rules characterise different institutional traditions?

By providing a harmonised description of institutional rules, the CRdb enables comparative research that was previously impossible using dispersed archival sources.

The Common Rules Database originated from research on historical commons in Europe. These self-governing Institutions for Collective Action regulated the use of shared resources such as forests, pastures and water through detailed bodies of written regulations. Because many commons survived for centuries, they offer a unique opportunity to study institutional governance over the long term.

Despite the richness of these historical sources, comparative research remained extremely difficult. Regulations differed in language, structure and terminology, making systematic comparison across institutions and countries nearly impossible.

The CRdb was therefore developed to create a common analytical language for institutional governance. Its original aim was to enable the comparative study of historical commons across Europe, but the methodology has broader relevance for the study of Institutions for Collective Action more generally. The project was inspired by Elinor Ostrom’s ambition to develop a grammar of institutions while adapting this approach to the realities of historical sources and long-term comparative research.

Developing the Common Rules Database was a lengthy and carefully considered process. Before any historical material was entered, considerable effort was devoted to designing a database architecture that would capture the richness of historical regulations while remaining suitable for comparison across countries and centuries. The structure of the database, the coding strategy and the analytical categories were refined through extensive discussion before data collection began. Every methodological decision was subsequently documented in an extensive codebook to ensure transparency, consistency and reproducibility.

An important methodological consideration concerned the representativeness of the available sources. Historical regulations have generally survived only for institutions that existed for relatively long periods. As a result, archival material is inevitably biased towards successful institutions. Rather than ignoring this limitation, the CRdb explicitly recognises this potential survivorship bias and documents the assumptions underlying its methodological choices.

Every institution included in the database covers at least two centuries of documented governance, with at least one surviving change in its regulations over that period. Historical regulations are translated into modern English before being systematically coded according to the Common Rules codebook.

Each individual rule is coded with information on:

• its content and scope (for example whether it applies generally or only to particular persons, locations or activities);
• the type of institutional arrangement it represents (such as obligations, permissions or prohibitions);
• the sanctions attached to the rule, including their severity, escalation for repeated offences and liability provisions.

Importantly, the Common Rules Database records successive bodies of regulations, allowing researchers to compare regulations issued at different moments in an institution’s history. The database itself does not trace individual rules through time or reconstruct rule genealogies. Instead, it provides the harmonised empirical foundation upon which longitudinal analyses of rule development can be built.

The Common Rules Database is organised as a relational database consisting of four interconnected levels:

• Institution: general descriptive information about each Institution for Collective Action.
• Regulation: successive bodies of regulations issued by each institution.
• Rule: the individual rules contained within each regulation.
• Sanction: the sanctions associated with individual rules.

This hierarchical structure enables researchers to move seamlessly between institutional, regulatory and rule-level analyses.

The Common Rules Database led to the following publications

• Laborda Peman, M. and De Moor, T., 2016. History and the commons: A necessary conversation. International Journal of the Commons, 10 (2), 517-528.
• De Moor, T., Lana Berasaín, J.M., Laborda Peman, M., van Weeren, R. & Winchester, A., 2016. Ruling the commons. Introducing a new methodology for the analysis of historical commons. International Journal of the Commons, 10 (2), 529-588.
• De Moor, T. and Weeren, R. van, 2014. Controlling the commoners: Methods to prevent, detect, and punish free-riding on Dutch commons in the early modern period. The Agricultural history review 62 (2), 256-277.

Although the Common Rules Database (CRdb) was originally developed using regulations from European pasture commons between c. 1300 and 1900, its underlying methodology has much broader applicability. The database was designed as a generic infrastructure for the comparative analysis of institutional rules and can therefore be extended to many other forms of Institutions for Collective Action (ICAs).

Despite their diversity, institutions such as guilds, mutuals, irrigation communities, cooperatives and contemporary citizen collectives often address similar collective action problems. They do so by developing formal governance arrangements concerning membership, decision-making, resource management, monitoring, conflict resolution and sanctioning. Because these governance principles are shared across many institutional forms, the Common Rules methodology provides a common analytical framework for studying their similarities and differences.

Extending the CRdb beyond historical commons will considerably broaden the scope for comparative institutional research. It enables researchers to investigate how different types of institutions organise cooperation, how governance arrangements vary across sectors and regions, and how institutional rule systems respond to changing social, economic and environmental circumstances. The database thereby provides an empirical basis for comparative research on institutional diversity while remaining sufficiently flexible to accommodate new institutional forms and analytical approaches.

The CRdb was intentionally designed as an evolving research infrastructure. As new case studies become available, additional institutional traditions can be incorporated using the same coding principles, allowing the database to grow cumulatively while maintaining methodological consistency. At the same time, new analytical techniques can be integrated with the existing infrastructure, ensuring that the database continues to support innovative forms of institutional research.

The methodological framework developed for the CRdb has already been adopted and extended in several research projects, demonstrating both its robustness and its adaptability.

• Dr Pieter Steenbergen applied the Common Rules methodology to the study of Dutch consumer cooperatives from the late nineteenth century onwards. His work reconstructed the regulations of consumer cooperatives and demonstrated how the methodology can be applied to institutional forms beyond commons. Steenbergen, P. (2024). Van ons, voor ons. 150 jaar veerkracht van consumentencoöperatie Coop. Aalten: Fagus. Van ons, voor ons. 150 jaar veerkracht van consumentencoöperatie Coop.
• Grant T. Halliday, in collaboration with Dr Florian Grisel, analysed the regulations of Spanish cofradías (fishery cooperatives). Their work employed the CRdb coding methodology and prepared a new corpus of regulations that can be incorporated into the database, illustrating the potential for expanding both its geographical and institutional coverage.
• Dr Damion J. Bunders extended the analytical possibilities of the CRdb by combining its historical coding methodology with Institutional Grammar, the framework developed by Crawford and Ostrom for analysing institutional statements. This work demonstrated how complementary analytical frameworks can enrich the study of institutional governance while building on the existing database infrastructure. Bunders, D.J. & De Moor, T. (2024). Using the Institutional Grammar to understand collective resource management in a heterogeneous cooperative facing external shocks. Regulation & Governance. https://doi.org/10.1111/rego.12607
• Dr Marianne Groep-Foncke and Dr. Tine De Moor explored the application of Large Language Models (LLMs) to the analysis of extensive collections of historical regulations. Their work illustrates how recent developments in artificial intelligence may support the interpretation, coding and exploration of large regulatory corpora while maintaining the methodological rigour required for historical research. Groep-Foncke, M. & De Moor, T. Easily accessible (small) LLMs in historical studies: opportunities, limitations, pitfalls.

Together, these studies demonstrate that the Common Rules Database is more than a repository of historical regulations. It is a flexible methodological and technical infrastructure that can be expanded to new institutional domains, enriched through complementary analytical approaches and continuously adapted to emerging developments in digital humanities, computational social science and institutional analysis.