How do open standards advocates define 'open standards'?

Answer: There are a few different takes on this question.

The Open Source Initiative (OSI), the organization responsible for reviewing and approving licenses as Open Source Definition (OSD) conformant, says "an ‘open standard' must not prohibit conforming implementations in open source software." OSI provides a list of five criteria an open standard must satisfy. "If an ‘open standard' does not meet these criteria, it will be discriminating against open source developers," the site says:

1. No Intentional Secrets: The standard must not withhold any detail necessary for interoperable implementation. As flaws are inevitable, the standard must define a process for fixing flaws identified during implementation and interoperability testing and to incorporate said changes into a revised version or superseding version of the standard to be released under terms that do not violate the OSR.
2. Availability: The standard must be freely and publicly available (e.g., from a stable web site) under royalty-free terms at reasonable and non-discriminatory cost.
3. Patents: All patents essential to implementation of the standard must:
   • be licensed under royalty-free terms for unrestricted use, or
   • be covered by a promise of non-assertion when practiced by open source software
4. No Agreements: There must not be any requirement for execution of a license agreement, NDA, grant, click-through, or any other form of paperwork to deploy conforming implementations of the standard.
5. No OSR-Incompatible Dependencies: Implementation of the standard must not require any other technology that fails to meet the criteria of this Requirement.

The Free Software Foundation Europe (FSFE) collaborated with other individuals and organizations in the tech industry, politics, and community to outline a different five-point definition. According to the FSFE, an open standard refers to a format or protocol that is:

1. subject to full public assessment and use without constraints in a manner equally available to all parties;
2. without any components or extensions that have dependencies on formats or protocols that do not meet the definition of an Open Standard themselves;
3. free from legal or technical clauses that limit its utilisation by any party or in any business model;
4. managed and further developed independently of any single vendor in a process open to the equal participation of competitors and third parties;
5. available in multiple complete implementations by competing vendors, or as a complete implementation equally available to all parties.