Final answer:
Avoiding double counting in GDP measurements is essential to prevent overestimation of an economy's value, ensuring the value of output reflects actual income.
Step-by-step explanation:
You must avoid double counting when measuring GDP because double counting overestimates the value of goods and services in an economy, leading to an inaccurate representation of a country's economic output. Gross Domestic Product (GDP) is defined as the current value of all final goods and services produced within a nation in a given year. Final goods refer to those that are at their furthest stage of production. To avoid the problem of double counting, statisticians only count the value of final goods and services, excluding intermediate goods which are used in the production of final goods. This ensures that the value of a nation's output equates correctly to the nation's total income, providing a true reflection of economic activity.