Committees can also set up sub-committees (e.g. the Subcommittee on Human Rights) and temporary committees to deal with a specific topic (e.g. on extraordinary rendition). The chairs of the Committees co-ordinate their work through the "Conference of Committee Chairmen". When co-decision was introduced it increased the Parliament's powers in a number of areas, but most notably those covered by the Committee on the Environment, Public Health and Food Safety. Previously this committee was considered by MEPs as a "Cinderella committee"; however, as it gained a new importance, it became more professional and rigorous, attracting increasing attention to its work.