There are several reasons for the continually increasing popularity of HPSG. Cooper hpsg-encyclopedia notes that even if HPSG - as linguistic formalism - is a combination of various theories, it offers a rigorous framework for grammar development through its foundation on unification of feature structures. Shieber shieber-ubg mentions the support for subcategorization and semantic representation as important qualities of HPSGs. Furthermore, Uszkoreit uszkoreit-hpsg-note lists key components of the HPSG formalism that explain the impact it had on grammar development, such as:
The Head-Driven component of the HPSG name reveals one of the underlying principles of this formalism. The most important element of a phrase is its lexical head [Pollard and Sag1994]. The lexical head incorporates both syntactic information (such as part of speech and dependency relations with other constituents) and semantic information. Lexical entities, in general, are information-rich structures, with feature values from the type signature (an inheritance hierarchy, as introduced in Chapter 2). This lexical-centered organization of HPSG eliminate redundancies, therefore the amount and complexity of phrasal rules is greatly reduced [Cooper1996].