FACA identifies four sources of authority for establishing an advisory committee:

1. (a) Required by statute. By law where Congress establishes an advisory committee, or specifically directs the President or an agency to establish it (non-discretionary);
2. (b) Presidential authority. By Presidential directive (non-discretionary);
3. (c) Authorized by statute. By law where Congress authorizes, but does not direct the President or an agency to establish it (discretionary); or
4. (d) Agency authority. By an agency under general authority in title 5 of the United States Code or under other agency-authorizing statutes (discretionary).