Rituals are sometimes said to exhibit formality because their performance proceeds according to a fixed set of specifications. Although these specifications need not exist in written form, they can be thought of as resembling the specifications contained in musical scores. Both function as guidelines for performers and both can be invoked to assess the extent to which a performance was correct. But are ritual scores - if such things exist - really like musical scores? And is the correctness of a ritual performance - its being an instance of a given ritual type -just a matter of compliance with a score? If not, then what else is involved in our grouping together certain performances as performances of one and the same ritual?