The extension of variation analysis to the level of discourse involves refining the notion that variants are semantic equivalents. Discourse variables may be determined on the basis of common discourse function. In the absence of a semantic tie the isloation of a variable begins with the salience of a variant and proceeds via examinations of its distribution to postulating a variable and mapping the alternative variants. This procedure is illustracted by an analysis of a socially diagnostic discourse feature– the set-marking tag. Its higher frequency in working- class sppeech stimulates the search for alternative favoured forms. One hypothesis, derived from Bernstein's notion of codes, is that the tags mark an orientation to “particularistic” rather than “ universalistic” meanings. It follows that a favoured alternative to the tag may be realised as general reference. (Discourse variables; variation theory; codes and social dialects; Australian English.)