The general rule of making research data accesible: Data should be as open as possible and as closed as necessary.

Research data are usually made accessible in a form of datasets, which means sets which are a separate elements including data related to one publication, scientific project or experiment.

FAIR rules have been created  to help scientists to prepare and make research data accessible.
FAIR stands for an acronym of four English adjectives depicting how the research data should look like:

Findable
  • a dataset provided with metadata allowing to find this set both by people and by computer machines
  • the dataset has a unique identifier (i.e. DOI), which is also the element of metadata description
  • metadata are indexed in widely available databases enabling to perform a database search
Accessible
  • the access to the dataset, at least, to metadata is directly possible due to a unique identifier and does not require any additional tools or software
  • metadata are always available, even if the dataset has been deleted or transferred
Interoperable
  • data and metadata are delivered in a format enabling to be read easily and processed both by people and computers
  • datasets and metadata describing them include references to other related resources
Reusable   
  • metadata include numerous attributes describing precisely the dataset and enabling users to define their usefulness for their own research
  • the dataset includes the license defining the explicit conditions for reusing and processing data
  • metadata distinctly define the author and the place of creating data
  • metadata are created according to generally accepted specific standards for each discipline and type of data

The rules are not rigid, but should be treated as guidelines to use data appropriately. FAIR rules have been created and have been still developed mainly to make data accessible both for users and searching databases computer software without the help of a man.

FAIR rules have been still developed and specified by the international society. The GO FAIR initiative organises meetings and workshops about implementing FAIR rules. 'Metadata 4 Machines' workshop, focuses on the possibility to create metadata understood in the best way for computer programmes, is one of the initiatives.