Once Tech’s Favorite Economist, Now a Thorn in Its Side

Paul Romer’s call for government activism, particularly toward the big tech companies, reflects “a profound change in my thinking.”

Paul Romer was once Silicon Valley’s favorite economist. The theory that helped him win a Nobel prize — that ideas are the turbocharged fuel of the modern economy — resonated deeply in the global capital of wealth-generating ideas. In the 1990s, Wired magazine called him “an economist for the technological age.” The Wall Street Journal said the tech industry treated him “like a rock star.” Not anymore. Today, Mr. Romer, 65, remains a believer in science and technology as engines of progress. But he has also become a fierce critic of the tech industry’s largest companies, saying that they stifle the flow of new ideas. He has championed new state taxes on the digital ads sold by companies like Facebook and Google, an idea that Maryland adopted this year.