Effective communication
The legal standard under the ADA requiring that communications with people with disabilities be 'as effective as' communications with non-disabled people.
The 'effective communication' standard appears in ADA Title II (state/local government) and Title III (public accommodations). It doesn't prescribe specific accommodations; it requires that whatever methods are used produce communication that's as effective as what non-disabled individuals receive.
For live events, this typically translates to providing live captions and offering accommodations on request — sign language interpretation for known deaf attendees, accessible materials, etc. The choice of accommodation can be informed by the requesting individual's preference.
Pattern-of-non-response to accommodation requests is a much stronger litigation signal than isolated technical failures. Documenting accessibility decisions and accommodation responses matters operationally.