Similarities and differences between new trade theory and comparative advantage theory

New trade theory explains intra-industry trade and comparative advantage theory explains inter-industry trade; The assumption of new trade theory is imperfect competitive market, while the premise of comparative advantage theory is perfect competitive market; Comparative advantage theory is studied from the perspective of supply, and new trade theory is also explained from the perspective of demand; The new trade theory emphasizes the role of differentiated products in international trade, while the comparative advantage theory assumes that all products are homogeneous. The new trade theory introduces economies of scale, and the theory of comparative advantage assumes that returns to scale remain unchanged.