Final answer:
The Bureau of Economic Analysis (BEA) of the U.S. Department of Commerce measures GDP by estimating its value based on the quantities of goods and services produced and their prices.
Step-by-step explanation:
Economists measure GDP by taking the quantities of all goods and services produced, multiplying them by their prices, and summing the total. The Bureau of Economic Analysis (BEA) of the U.S. Department of Commerce is responsible for estimating GDP. They piece together estimates from a variety of sources to calculate the value of the output of all goods and services produced within the country in a year.