Open data

Abstract painting

What are Open Data?

Open data are data that anyone can access, use or share. For data to be open, they should have no limitations that prevent them from being used in any particular way.

Open data must be free to use, but this does not mean that they must be free to access – a reasonable cost is one that reflects how much it costs the holders of the data to reproduce them more widely. Once the user has the data, they are free to use, reuse and redistribute them – even commercially.

Read more: Why do we need Open Data?

Open data have the potential to help grow economies, transform societies and protect the environment, for example: 

  • Innovation and growth in data-driven businesses
  • Opportunities for governments from growing data economies
  • Impact on society and public policy through improved mobility, new ways of working, and data-driven policy-making
  • Benefits for the environment, through research collaborations that increase agricultural productivity

Open data can help make governments more transparent. They can provide the evidence that public money is being well spent and policies are being implemented.

However, it is vital for data to be clearly and thoroughly licensed to make sure that they are fully usable as open data. In the case of COVID19, for example, hosts regularly updated open data on infection rates, death rates and testing on a dedicated platform.

Read more: Open Data platforms and data aggregators

A platform is a major piece of software on which smaller pieces of software and content can be run. Open data platforms are pieces of software that make it simpler to publish and manage open data on the Web.Data aggregators and portals provide access to a number of datasets in one place.

Aggregators may be run by national governments (for example, see, municipal authorities, international organisations or domain-specific interest groups such as an academic community. There are over 500 open data portals listed on the directory

Read more: Open Data Licenses


Why license open data?

Without a licence, data are not truly open. A licence tells anyone that they can access, use and share your data. Unless you have a licence, data may be ‘publicly available’, but users will not have permission to access, use and share them under copyright or database laws.

Open Government

Some government publishers have chosen to develop their own licences. For example, the UK and French governments use custom open government licenses. The best examples are short, compatible with widely used licences, and easy to comply with.

Under these, you are free to:

  • Copy, publish, distribute and transmit the information;
  • Adapt the information;
  • Exploit the information commercially and non-commercially for example, by combining it with other information, or by including in your own product or application.

For more on data licences, see the Open Data Institute’s Data Certificates and Tim Berners-Lee’s 5 star deployment scheme for open data.

Read more: Creative Commons licensing


Creative Commons licences are widely used for open content. Version 4.0 explicitly considers data licensing.

There are three Creative Commons types of open licence, with different levels of attribution required:

  • Public domain (CC0): CC0 is the ‘no copyright reserved’ option in the Creative Commons toolkit. It effectively means relinquishing all copyright and similar rights that you hold in a work and dedicating those rights to the public domain, so that anyone may freely build upon, enhance and reuse the works for any purposes without restriction under copyright or database law.
  • Attribution (CC-BY v4.0): Under this licence you can share data by copying and redistributing them in any medium or format. You can also adapt it by remixing, transforming and building upon materials for any purpose, even commercially. The licensor cannot revoke these freedoms, as long as you follow the license terms.
  • Attribution & Share-alike (CC-BY-SA v4.0): Under this option, you must give appropriate credit, provide a link to the license, and indicate if changes were made (this is the ‘attribution’ part of the licence). You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original (‘Share-alike’).

Source: Open Data Institute, ODI.


See also

Learning about Data: What do we mean by data?
Health and Wellbeing Data: What forms do health and wellbeing data take?
Data for Advocacy: How can we use data to advocate for social change?
Data Art: How can data art help improve health and wellbeing?
Telling Stories with Data: Why tell stories using data?
COVID19 Data: What can data tell us about the pandemic?