In 2025 alone, Dimensions.com tracked more than 8.7 million new research outputs. As of October 2026, it has tracked a further 6 million.

These numbers, inclusive of more than just peer-reviewed publications, demonstrate the huge volume of data which is available online. As this number continues to grow, it is more important ever that data are findable, organised, and useful.

Metadata are the data which describe this information: what it is, what it’s about, where it has come from, and how to use it. In short, metadata help turn diverse information into something people can actually use.

In this article, we answer what metadata are, the different types of metadata, and explore why metadata are important for academic publishing, particularly Open Access.

Defining metadata

The meaning of metadata can be understood by breaking down the word itself.

‘Meta’ is a common prefix for something that is self-referential. On the other hand, ‘data’ refers to information. Therefore, metadata are data about data or in other words, information about information.

If we are to use the example of a book, the main body of the text would be the data. Whereas, the book’s metadata would include the title page, author and publisher information, price, and synopsis, amongst other elements.

We can also understand metadata as the subject, sender information, or date which accompanies an email, or the geolocation which is attached to a photograph.

Metadata provide the all-important context which is the starting point for finding, organising, and understanding information. This is why good metadata are essential, especially in today’s research environment where millions of articles, preprints, and datasets are published each year.

Metadata are what make these outputs findable, citable, and reusable.

Different types of metadata

The various types of metadata can be separated into distinct categories. The three most prominent types are descriptive, administrative, and structural metadata:

• Descriptive metadata are used to describe and find a resource. Examples can include the author’s name, title, abstract, or the Digital Object Identifier (DOI).
• Administrative metadata explain how the data can be managed, including access rights, copyright details, and ownership.
• Structural metadata describe how the data are organised. This may pertain to files within a larger dataset or the chapters within a book.

Importantly, these three categories are not exhaustive. Technical metadata, preservation metadata, and provenance metadata are also types of metadata but they are commonly grouped as sub-sections of administrative data.

Research metadata also rely on persistent identifiers, which are permanent and standardised codes which trace various components of the research process as they navigate the digital space. These unique codes include:

• Digital Object Identifiers (DOIs) for research outputs;
• Open Researcher and Contributor ID (ORCID) for the researcher;
• Research Organisation Registry (ROR) for the institution;
• Funder and grant IDs for who funded the research.

Why do we need metadata?

Without metadata, it would be impossible to efficiently navigate the vast volumes of information that are made available to us online and in physical formats too.

In response to this excess of information, metadata form the backbone of the tools and platforms that enable academics to discover relevant research and ensure their own work is visible.

Metadata are not only important for researchers. For institutions, metadata are an important tool for identifying and organising data relating to outputs from their organisation. This is similarly true for funders. Metadata allow them to track outputs corresponding to individual grants which have funded the research.

Why are metadata important to Open Access?

Open Access makes research publications freely accessible to the entire scholarly community, at no cost to the reader. Open Access articles can also be downloaded and reused by others, maximising its visibility and encouraging greater impact.

However, these benefits of Open Access are impeded if scholars are unable to find the work in the first instance or if the conditions on how it can be used remain unclear. This is where metadata come in.

Descriptive metadata are essential for discovery. They are what search engines or databases read, so the quality of these metadata ultimately dictate how easily research can be found. For example, without an abstract or keywords, a paper may never appear in a database search.

Alternatively, administrative metadata, particularly copyright and funder information, are further key for achieving openness. If an article is free to read but has no licence information, readers may be unaware they can share or reuse it.

While these two examples are good at illuminating how metadata support the overarching purpose of Open Access, it is worth noting the specific relationships between key actors in the publishing ecosystem and metadata.

Submitting metadata

Publishers such as MDPI have an incredibly important role in delivering high-quality metadata. It is their responsibility to register the metadata, ensuring they are well-structured and correctly formatted, making them available to libraries and indexing databases.

However, before this can happen, the initial information must be provided by the researchers themselves. It is their obligation to make sure this information is complete and correct.

Key metadata to include are the title, keywords, abstract, author name(s), author affiliations, ORCID information, funding information, data availability statements and more.

Ultimately, having well-structured and thorough metadata has direct implications on the discoverability of research, so they should be as comprehensive as possible.

Scholars are asked to insert metadata at the submission stage, though they will also feature in the manuscript itself. The front page will include the title, author name(s), and affiliations, while the back matter will feature various statements such as funding, author contributions (CRediT), competing interests and data availability.

Best practices

There are a few things authors should consider when submitting their metadata. These will serve to influence the quality and utility of metadata for others, once the research is shared:

• Link to the authors’ ORCID accounts: This will ensure it is connected to their other works to ensure a complete publication record.
• Attach data: If raw data or code represent a large component of the study, these should be deposited in an openly accessible repository and attached to the article using a DOI.
• Funder information: Funder information should be carefully filled out, with any relevant funder codes added to the manuscript.
• Licencing: Pay attention to the license your work will be published under. This has implications for how your work can be used by others.
• Keywords: Choosing keywords that are relevant to your area of study helps relevant scholars to interact with it.

What is FAIR data?

Metadata should also be structured so that both humans and machines can find, interpret, and reuse it.

This forms the basis of the FAIR Guiding Principles for Data Management and Stewardship, which are important guiding principles for scholars to be aware of.

Here, FAIR stands for:

• Findability: Metadata and data should be easy to find by humans and computers.
• Accessible: The user needs to know how the data can be accessed.
• Interoperable: Data must be integrated with other data and applications for analysis, storage, and processing.
• Reusable: Data must be clearly described so they can be replicated or combined in different settings.

To learn more about FAIR Data, read our article ‘Understanding and Practicing FAIR Data’.

The role of publishers: structuring and registering metadata

Once this information is provided by researchers, publishers turn this information into formal metadata which can be shared with indexing databases.

Indexing services such as Web of Science, Scopus, Directory of Open Access Journals (DOAJ), Google Scholar, and more depend on complete metadata in order to display and feature articles. In addition, DOAJ sets its own clear criteria for OA journals, highlighting the importance of metadata open scholarship.

Before it can be registered across databases, they must be converted into a metadata schema. This is a set structure or set of rules for how they can be displayed.

Widely used metadata schemas include:

• Dublin Core – for descriptive metadata
• JATS XML – for journal articles
• DataCite – for datasets

Metadata schemas are important as they have direct implications on the interoperability of your metadata.

Clear structures allow metadata to be recorded in a consistent way, ensuring they are compatible with the many different platforms they are utilized by.

Click here to learn more about interoperability and why it is important to open science.

MDPI’s approach to metadata

As the leading Open Access publisher, MDPI is committed to upholding the highest standards of metadata quality.

All research published within MDPI’s journals is entirely Open Access, meaning it is free to read, download, and reuse. All metadata attached to these articles are made quickly available through several channels so that libraries, indexing databases, or other platforms can access it.

All MDPI’s newly published metadata are deposited to Crossref approximately 24 hours after publication. MDPI also maintains an OAI-PMH interface for metadata sharing, with records in Dublin Core and AGRIS formats.

Standardized metadata are also built into the publications themselves. The abstract page of each paper embeds Dublin Core, PRISM, and Google Scholar metadata in its source code, which actively empowers harvesting and indexing.

Additionally, MDPI’s AI-powered ROR Entity Search API turns messy, free-text institutional metadata into standardised ROR IDs to support accurate analytics and organisation-aware workflows across MDPI and beyond.

High-quality metadata benefit the entire research ecosystem

MDPI’s rigorous approach to metadata serves to benefit researchers, institutions and funders alike, recognizing that metadata directly inform the process of making scientific outputs available to the community.

For authors, MDPI’s approach to metadata ensures their research is findable. Given that Open Access increases the visibility of your work, which commonly translates into greater impact through more citations, this is particularly important.

Moreover, it also allows institutions and funders to easily find scholars’ work, therefore making it simpler for researchers to demonstrate compliance with Open Access requirements. Again, this is essential in the context of the growing number of OA mandates across the globe.

Using metadata: how librarians’ benefit

As digitalization continues to move scholarly communication online, the role of libraries have evolved to include the role of managing institutional repositories. Amongst other responsibilities, they ensure records are clear and consistent and that outputs are preserved.

Good metadata are what makes that possible. They allow for the efficient discovery, management, and preservation of resources. When records are structured and tagged consistently, students and other readers can easily find them. Consistent records are also easier to manage and preserve over time, so collections stay useful long after they are initially deposited

Furthermore, good-quality metadata bolster a repository’s visibility since they determine which digital collections from institutions show up across search engines.

MDPI’s commitment to advancing open science

The importance of metadata for academic research cannot be understated. They are what make research outputs findable, citable, and reusable, and aid in navigating the complex information available online.

MDPI continues to lead the global transition towards Open Access and understands the value of complete and high-quality metadata.

Accordingly, MDPI encourages all its authors to publish their findings in as much detail as possible. On each journal webpage, MDPI provides instructions for authors to help authors prepare their manuscripts.

We’re dedicated to giving you all the information you need to understand Open Access. Our article All You Need to Know About Open Access covers a range of topics.