Later, Phelps developed a long-term growth theory based on education and technical advances. However, this contribution was so far ahead of its time that the profession did not discover its importance until a quarter-century later, when theorists were developing endogenous growth theories.
后来，菲尔普斯发展了基于教育和技术进步的长期增长理论。但是，这一贡献是如此超前，以致直到15年后当理论学家在研究了内生增长理论时才发现了它的重要性。