LEED is updated through a regular development cycle for revisions to the rating system. There are three basic types of LEED development:
Implementation and maintenance of current version: LEED rating systems are continually improved through published updates such as quarterly addenda.
LEED rating system adaptations: Credit adaptations address both specific construction types and international projects, meeting the needs of projects that would otherwise be unable to participate in LEED. For example, the LEED BD+C: Schools rating system can be seen as a rating system adaptation of LEED for the purpose of serving school projects. Alternative Compliance Path (ACP) can be an example of a credit adaptation for international projects. ACPs enable international projects to earn the appropriate prerequisites/credits by allowing them to meet international standards or their local standards instead of United States–based standards. Rating systems are also periodically updated to cover more ACPs.
Next version of LEED: Rating systems are evaluated and revised periodically.
Additionally, the LEED Pilot Credit Library plays an important role in the evolution of LEED. Pilot credits are tested across all rating system types and credit categories and include credits proposed for the next version of LEED. Project teams can pursue any of these pilot credits under the Innovation credit category and earn points by providing USGBC with feedback on the credit. With these feedbacks, USGBC refines the pilot credits and worthwhile credits, which are then added as actual credits to the new LEED rating system.