The subject-side parameter, also called the specifier–head parameter, is a proposed parameter within generative linguistics which states that the position of the subject may precede or follow the head. In the world's languages, Specifier-first order (i.e., subject-initial order) is more common than Specifier-final order (i.e., subject-final order). For example, in the World Atlas of Linguistic Structures (WALS), 76% of the languages in their sample Specifier-first (either SOV or SVO). In this respect, the subject-side parameter contrasts with the head-directionality parameter. The latter, which classifies languages according to whether the head precedes or follows its complement, shows a roughly 50-50 split: in languages that have a fixed word order, about half have a Head-Complement order