Neoclassical growth model - Wikipedia, the free encyclopedia In 1987, Solow received the Nobel Prize in Economics for his work. Solow was also the first economist to develop a growth model which distinguished between vintages of capital. In Solow's model, new capital is more valuable than old (vintage) capital because—since capital is produced based on known technology, and technology improves with time—new capital will be more productive than old capital. Both Paul Romer and Robert Lucas, Jr. subsequently developed alternatives to Solow's neo-classical growth model. Today, economists use Solow's sources-of-growth accounting to estimate the separate effects on economic growth of technological change, capital, and labor.