There are two types; human-readable data that is marked up so that it can also be read by machines (examples; microformats, RDFa, HTML) or data file formats intended principally for processing by machines (RDF, XML, JSON).
Machine readable is not synonymous with digitally accessible. A digitally accessible document may be online, making it easier for a human to access it via a computer, but unless the relevant data is available in a machine readable format, it will be much harder to use the computer to extract, transform and process that data.
For purposes of implementation of the Government Performance and Results Act (GPRA) Modernization Act, the Office of Management and Budget (OMB) defines "machine readable" as follows: "Format in a standard computer language (not English text) that can be read automatically by a web browser or computer system. (e.g.; xml). Traditional word processing documents and portable document format (PDF) files are easily read by humans but typically are difficult for machines to interpret. Other formats such as extensible markup language (XML), (JSON), or spreadsheets with header columns that can be exported as comma separated values (CSV) are machine readable formats. As HTML is a structural markup language, discreetly labeling parts of the document, computers are able to gather document components to assemble Tables of Content, outlines, literature search bibliographies, etc. It is possible to make traditional word processing documents and other formats machine readable but the documents must include enhanced structural elements."
- "A Primer on Machine Readability for Online Documents and Data". Data.gov. 2012-09-24. Retrieved 2015-02-27.
- OMB Circular A-11, Part 6, Preparation and Submission of Strategic Plans, Annual Performance Plans, and Annual Program Performance Reports
- Open data
- Linked data
- Machine-Readable Documents
- Human-readable medium
- Section 10 of the GPRA Modernization Act (GPRAMA), which requires U.S. federal agencies to publish their strategic and performance plans and reports in machine-readable format, like Strategy Markup Language (StratML)
- President Obama's Executive Order Making Open and Machine Readable the New Default for Government Information
- OMB M-13-13, Open Data Policy: Managing Information as an Asset, which requires agencies to use open, machine-readable, data format standards