The paper by Carol Corrado, Charles Hulten, and Daniel Sichel examines the impact of excluding intangible investments from published GDP data on the measurement of U.S. economic growth. Traditionally, macroeconomic data has excluded most intangible investments from GDP, leading to an underestimation of the role of intangibles in economic growth. The authors estimate that up to $800 billion is still excluded from published data, resulting in an overestimation of the role of tangible capital and a significant underestimation of the contribution of intangible capital to business growth. To address this issue, the authors incorporate intangible capital into the standard sources-of-growth framework used by the Bureau of Labor Statistics (BLS). They find that including intangible assets significantly alters the observed patterns of U.S. economic growth. Specifically, the rate of change of output per worker increases more rapidly when intangibles are counted as capital, and capital deepening becomes the dominant source of growth in labor productivity. The role of multifactor productivity is diminished, and the labor share of income has decreased significantly over the last 50 years. The paper also discusses the theoretical basis for treating intangible expenditures as capital rather than intermediate inputs, the criteria for capitalizing intangibles, and the methods for measuring intangible investment and capital. It provides estimates of business investment in intangibles by decade, showing that intangible investments have accounted for a significant portion of economic growth over the past five decades. The authors conclude that the inclusion of intangible capital in economic growth models is crucial for a more accurate understanding of the factors driving U.S. economic development.The paper by Carol Corrado, Charles Hulten, and Daniel Sichel examines the impact of excluding intangible investments from published GDP data on the measurement of U.S. economic growth. Traditionally, macroeconomic data has excluded most intangible investments from GDP, leading to an underestimation of the role of intangibles in economic growth. The authors estimate that up to $800 billion is still excluded from published data, resulting in an overestimation of the role of tangible capital and a significant underestimation of the contribution of intangible capital to business growth. To address this issue, the authors incorporate intangible capital into the standard sources-of-growth framework used by the Bureau of Labor Statistics (BLS). They find that including intangible assets significantly alters the observed patterns of U.S. economic growth. Specifically, the rate of change of output per worker increases more rapidly when intangibles are counted as capital, and capital deepening becomes the dominant source of growth in labor productivity. The role of multifactor productivity is diminished, and the labor share of income has decreased significantly over the last 50 years. The paper also discusses the theoretical basis for treating intangible expenditures as capital rather than intermediate inputs, the criteria for capitalizing intangibles, and the methods for measuring intangible investment and capital. It provides estimates of business investment in intangibles by decade, showing that intangible investments have accounted for a significant portion of economic growth over the past five decades. The authors conclude that the inclusion of intangible capital in economic growth models is crucial for a more accurate understanding of the factors driving U.S. economic development.