Which metric measures a nation's economic strength by the total value of goods and services produced?

The metric that measures a nation's economic strength by the total value of goods and services produced is Gross Domestic Product (GDP). GDP quantifies the overall economic activity within a country during a specific period, usually calculated annually. It encompasses the sum of all finished goods and services produced within a country's borders and is a primary indicator used to gauge the health of a nation's economy.

GDP reflects not only the productivity of a nation's resources but also serves as a tool for comparing the economic performance of different countries. Higher GDP figures generally indicate a stronger economy, reflecting increased productivity and potentially higher living standards, as there may be more resources available for public services and investments.

The other options represent different dimensions of economics and human welfare. The Human Development Index (HDI) evaluates social and economic factors contributing to human development beyond mere economic performance, while Purchasing Power Parity (PPP) considers the relative purchasing power of currencies, rather than total economic output. Per Capita Income provides a measure of the average income per person, which can indicate economic prosperity but does not encapsulate the total value of all goods and services produced. Thus, GDP is the most comprehensive measure for determining a nation's economic strength in terms of overall production.