European Data Portal

Open Data in a nutshell

Open Data in a nutshell



What is Open Data exactly? Various explanations exist. This section will offer a series of definitions. Furthermore, we will explain the differences between Open Data and PSI as well as Open Data and Open Government Data. Finally, we briefly explain why Open Data matters and what benefits can be expected.



Topics discussed in this chapter


General definition of Open Data

In order to provide a single definition of Open Data, we refer to the Open Definition (Open Knowledge, 2015) published by Open Knowledge. Open is in this case:

“Knowledge is open if anyone is free to access, use, modify, and share it — subject, at most, to measures that preserve provenance and openness.”

The term Open Data is very specific and covers two different aspects of openness:

  • The data is legally open, which in practice generally means that the data is published under an open licence and that the conditions for re-use are limited to attribution.
  • The data is technically open, which means that the file is machine readable and non-proprietary where possible. In practice, this means that the data is free to access for everybody, and the file format and its content are not restricted to a particular non-open source software tool.

Open Data can be freely used, modified, and shared by anyone. These properties are described in a licence. The fact that Open Data can be freely used in different ways does not necessarily mean that the data is available without charge. However, it is preferably downloadable via the Internet without charge (Open Knowledge, 2015).

To learn more about what Open Data is, please also refer to the relevant Online Training module about this: What is open data?

Do you know what Open Data is yourself, but want to provide training to your colleagues? Go to the Training Companion that helps you deliver training.


Public Sector Information and Open Government Data

Public Sector Information (PSI) is the wide range of information that public sector bodies collect, produce, reproduce, and disseminate in many areas of activity while accomplishing their institutional tasks. PSI may include (among others) social, economic, geographical, cadastral, weather, tourist, and business information. 

Open Government Data refers to the information collected, produced or paid for by the public bodies (PSI) and made freely available for re-use for any purpose. Open Government Data is published under an open licence and is free to use within private and public domains. 

In 2013, the G8 summit defined the importance of Open Government Data by creating the Open Data Charter. This charter emphasises the role that Open Data can play in both governance and growth stimulation. The charter defines five principles that nations that open up their data should follow. The 5 basic principles are shown in below.


Open Data Charter Principle

The Open Data Charter Principle


The Directive on the re-use of Public Sector Information (2003/98/EC), also known as the PSI Directive, provides a common legal framework for a European market for government-held data. Therefore, within the European Union – thanks to this PSI Directive – PSI acquires a specific legal meaning with a framework providing a minimum set of requirements. A revision of the PSI Directive was introduced in 2013 2013/37/EU (EUR-Lex, 2013). The main amendments are the breakaway from cost-based charging for PSI towards a margin-oriented fee, inclusion of certain cultural institutions as public sector bodies, increased transparency regarding calculation of the fees, and support to machine-readable and open formats. Currently, all European countries are in the process of completing the transposition of the revised PSI Directive.

Is PSI Different from Open (Government) Data? 

While the terms PSI and Open (Government) Data are used quite often without distinction (thus overlapping most of the times), a strict definition of PSI according to the PSI Directive would reveal certain discrepancies. One should keep in mind that both the PSI directive and the so-called Open Data Movement provide a set of rules and principles that may be practically implemented in a slightly different way within different countries and different existing legal frameworks. There are several distinguishing arguments that are further explained in Appendix 1 - The PSI Directive vs. Generally Acknowledged Open Data Features. In summary, the main difference is that PSI refers to data held by public sector bodies only, and that its re-use may, under certain circumstances, be charged for. If PSI is made available under an open licence, it is called Open Government Data. The general term Open Data also refers to other types of non public sector data that is freely available, for example social media data.


Figure 3

From PSI to Open Data


The benefits of Open Data 

Open Government Data is a wealth of untapped potential. As with any initiative within the public domain, it also involves expenditures and the effort of internal resources. Better understanding the benefits of Open Data can help accelerate the commitment around your Open Data initiative. The following overview provides more evidence of these benefits to support your initiative.

PSI that is generated and collected on a regular basis has a tremendous potential. The economic potential of PSI within the European Union goes beyond billions of Euros annually, with a potential to stimulate the overall economy and create new jobs. The economic study done as part of the European Data Portal project estimates the direct market size of Open Data to be 75.7 bn EUR in 2020 and the number of Open Data jobs to be almost 100,000 in 2020. The report Creating Value through Open Data can be found here:


Making information that is generated and collected by public sector entities available and re-usable is important for many reasons:

  • It provides citizens with a reliable knowledge base regarding government and public sector bodies’ activities. 
  • It enables them to take part in public sector bodies’ activities and therefore participate actively to the public choices (eDemocracy).
  • It represents the initial material for public or private stakeholders to develop new added-value services and supply them to citizens. 
  • It is one of the crucial tasks to fulfil the aim of the Digital Agenda for Europe to “deliver sustainable economic and social benefits from a digital single market based on fast and ultra-fast internet and interoperable applications” (Kolodziejski, 2013) 

Practically speaking, the benefits of Open Government Data may differ according to the type of stakeholder involved. These stakeholders can be divided into 3 main groups: governmental organisations, citizens and re-users. We will elaborate on various benefits for each of these stakeholder groups. 

Firstly, governments themselves are one of the main re-users of the data they collect themselves. Practice has proven that by publishing data, governments themselves start re-using it, which results in costs savings (Berners-Lee, 2015). The following quote illustrates this example: 

“This is why it should come a surprise that when the government of British Columbia began releasing Open Data in a centralised place, their Open Data portal, around one third of the site visits came from within government itself.” - Rogers, 2015

Publishing Open Data enables the sharing of information within governments in machine-readable interoperable formats, which results in reducing costs of information exchange and data integration, no or limited upstream data management, error reduction by having one copy instead of multiple ones, etc. This results in improved data management, in terms of both quality and efficiency, as well as an overall reduction in administrative costs. In fact, the Greater Manchester area has estimated that freedom of information requests cost public bodies over £4 million a year, while over 600 public officials a day are unable to find or use data that they require for their jobs, costing authorities over £8.5 million a year. By breaking down the silos that exist between the various departments, bodies, and layers of government and allowing a fluid data flow can have substantial efficiency gains. 

The economic analysis conducted by the European Data Portal estimates the accumulated cost savings for the EU28+ in 2020 to equal 1.7 bn EUR

There are further benefits to consider:

  • Opening up data can optimise your process internally. When data is open, none of your colleagues will have to go through an internal process to receive particular data. Many organisations have encountered the benefit of having their data open, simply because it takes less time to find data. Remember, your organisation will most probably be the most active re-user of your data. 
  • Not only your organisation, but also citizens will benefit from an improved – and perhaps faster – internal information structure. Processes will take less time, services can be digitalized, and citizens will benefit from more efficiency and transparency. A simple example might be to apply a single data provision to your services, thereby ensuring that users – citizens and / or businesses – will not have to keep on providing data you already have.
  • If your organisation’s data infrastructure may be outdated, your Open Data initiative might be a wonderful chance to achieve an internal change. Many organisations have taken the opportunity to redesign their internal data infrastructure and incorporated the publication of data as a main activity in working instructions. Talk with the managers within your organisation what the plans are concerning IT infrastructure on data level. 
  • By means of user feedback, you can improve the quality of your datasets. The power of the crowd, known as crowd sourcing, is a very efficient way of pooling resources to reach a given, sometimes surprising, result. 

Manchester City has published data, which they can now easily use internally. They can potentially save £8.5 million a year by reusing their own data. Check out the full story:


Secondly, by publishing PSI, government actions become more visible. This type of transparency helps both governments and citizens. It enables citizens to verify government actions. In turn, citizens’ understanding of government will increase and they will feel more empowered by increased access to information. This empowerment could stimulate democracy and participation in (local) government.
Some examples of the effects of these transparency benefits are spending transparency, such as agricultural subsidies and the press coverage of those data, and elections results (e.g. EP elections or national/regional elections) in EU Member States. For citizens there are several benefits, such as the aforementioned transparency, but also possible social and commercial value. Furthermore, as citizens are better informed, they can actively participate and cooperate with the (local) government. 

Besides the creation of social value, Open Data opens up possibilities for entrepreneurs. 


Open Data creates value for both citizens and private businesses after the release of a specific application. Social value for the public sector can generate commercial value for the private sector. Data is a key resource and as such, Open Government Data has tremendous commercial value. Since governments typically hold large amounts of information stored in all kinds of systems, opening up this data would lead to freeing up this potential. Hand in hand with Big Data, Open Government Data stimulates re-users to create new innovative products and services. Innovation is a key driver of long-term commercial success and stimulated by Open Data. It has a large potential to stimulate economic growth. In addition, the re-use can stimulate the improvement of processes, such as planning, quality and digitalization. For some businesses, this means an in-depth transformation of business models and therefore internal innovation can equally be achieved. 

There are numerous examples of re-use of Open Data as shown below: 


Figure 4

Examples of re-use of Open Data

The following figure summarises the main benefits presented in the previous paragraphs:

Benefits when Open Government Data is re-used


For more information about unlocking value from Open Data, please also refer to the relevant Online Training module about this: Unlocking value from open data

Do you want to learn more about Open Data publication and re-use examples in Europe? There is a specific section in the Library that offers multiple Use Cases

If you want to learn more about Digital Transformation and Open Data, you can read the report:



A growing number of new initiatives and start-ups re-use Open Data. Several organisations generate case studies and keep track of start-ups that re-use Open Data. Please look at the box below for more links to examples and case studies of Open Data re-use. Furthermore, most (national) Open Data portals have a page with re-use examples of their data. It is worthwhile looking at those as well. 

A growing number of new initiatives and start-ups re-use Open Data. Several organisations generate case studies and keep track of start-ups that re-use Open Data. Please look at the box below for more links to examples and case studies of Open Data re-use. Furthermore, most (national) Open Data portals have a page with re-use examples of their data. It is worthwhile looking at those as well.

For more value stories, look at the national Open Data portals and their case studies. The following webpages are useful as well.

Value Stories by Open Knowledge:


Open Knowledge


Code for America success stories:


Code For America data/#success-stories


The Open Data Institute Case Study page:


Open Data Institute


And the Open Data 500 website:


Open Data 500