History and theory alike suggest that General Purpose Technologies (GPT's), such as the steam engine or electricity, may play a key role in economic growth. In a previous paper (Helpman and Trajtenberg, 1994) we incorporated this notion into a Grossman-Helpman growth model, and explored the...

We develop a model of growth driven by successive improvements in `General Purpose Technologies' (GPTs), such as the steam engine, electricity, or micro-electronics. Each new generation of GPTs prompts investments in complementary inputs and impacts the economy after enough such compatible...

We develop a model of growth driven by successive improvements in 'General Purpose Technologies' (GPT's), such as the steam engine, electricity, or micro-electronics. Each new generation of GPT's prompts investments in complementary inputs, and impacts the economy after enough such compatible...

This paper analyzes the terrorist threat following 9/11, and explores its implications for defense R&D. First, it reviews the composition of defense R&D since 9/11: big weapon systems still command 30% of defense R&D spending (legacy of the Cold War), vis-a-vis just about 13% for intelligence...

Innovation and technological change, long recognized as the main drivers of long-term economic growth, are elusive notions that are difficult to conceptualize and even harder to measure in a consistent, systematic way. This book demonstrates the usefulness of patents and citations data as a...

This paper asks the question: Can we see evidence of General Purpose Technologies in patent data? Using data on three million US patents granted between 1967 and 1999, and their citations received between 1975 and 2002, we construct a number of measures of GPTs, including generality, number of...

This outstanding collection provides a fitting tribute to the diversity and depth of Paul David’s contributions. The papers included range from simulation models of the evolution of market structure in the presence of innovation, through historical investigations of knowledge networks and...