What was GDP designed to replace as a measure of economic performance?

Gross Domestic Product (GDP) was designed to replace Gross National Product (GNP) as a primary measure of economic performance. GNP measures the total economic output produced by the residents of a country, regardless of where that production takes place, while GDP focuses on the total output produced within a country’s borders, regardless of who produces it. The shift to GDP was made to provide a more accurate reflection of the economic activity occurring within a nation's economy, as it captures the strength and productivity of domestic industries more effectively.

GDP's broader focus allows policymakers and researchers to assess economic performance based on domestic consumption and investment, thus giving a clearer picture of economic health. This change was also intended to improve the comparability of economic data across nations, as GDP provides a standard measure that can be more easily understood and utilized on an international scale.