Opinions from T. E. Williamson and T. D. Carr 2003
- 'Goyocephale belongs to Pachycephalosauria'
- 'Goyocephale lattimorei belongs to Goyocephale'
- 'Gravitholus is a subjective synonym of Stegoceras'
- 'Gravitholus albertae is a nomen dubium'
- 'Homalocephale belongs to Pachycephalosauria'
- 'Homalocephale calathocercos belongs to Homalocephale'
- 'Ornatotholus is a nomen dubium'
- 'Pachycephalosauridae belongs to Pachycephalosauria'
- 'Pachycephalosaurinae belongs to Pachycephalosauridae'
- 'Pachycephalosaurus belongs to Pachycephalosaurinae'
- 'Prenocephale belongs to Pachycephalosaurinae'
- 'Prenocephale prenes belongs to Prenocephale'
- 'Sphaerotholus belongs to Pachycephalosaurinae'
- 'Sphaerotholus buchholtzae belongs to Sphaerotholus'
- 'Sphaerotholus goodwini belongs to Sphaerotholus'
- 'Stegoceras belongs to Pachycephalosauridae'
- 'Stegoceras brevis belongs to Stegoceras'
- 'Ornatotholus browni is a nomen dubium'
- 'Stegoceras lambei belongs to Stegoceras'
- 'Stegoceras validus is corrected as Stegoceras validum and belongs to Stegoceras'
- 'Stenopelix belongs to Pachycephalosauria'
- 'Stenopelix valdensis belongs to Stenopelix'
- 'Stygimoloch belongs to Pachycephalosaurinae'
- 'Stygimoloch spinifer belongs to Stygimoloch'
- 'Stegoceras edmontonense is a nomen dubium'
- 'Troodon sternbergi is recombined as Stegoceras sternbergi'
- 'Troodon wyomingensis is recombined as Pachycephalosaurus wyomingensis'
- 'Tylocephale belongs to Pachycephalosaurinae'
- 'Tylocephale gilmorei belongs to Tylocephale'
- 'Wannanosaurus belongs to Pachycephalosauria'
- 'Wannanosaurus yansiensis belongs to Wannanosaurus'
- 'Yaverlandia belongs to Pachycephalosauria'
- 'Yaverlandia bitholus belongs to Yaverlandia'