Which of the following refers to a potential mistake in measuring GDP where output is counted more than once?

The concept described as a potential mistake in measuring GDP, where output is counted more than once, is known as double counting. This phenomenon can occur when goods are counted at multiple stages of production, rather than just at their final sale to consumers. GDP aims to measure the total economic production of a country, and to accurately reflect this, it is crucial to only include the value of final goods and services in the calculation.

For example, if a manufacturer produces a component that is sold to a car manufacturer, who then includes that component in the price of the finished car, including both the component and the final car in GDP calculations would lead to double counting. Instead, GDP should include only the final sale—the sale of the car—to accurately represent the economy's overall production. This principle helps ensure that the GDP figure reflects the true economic output and maintains its integrity as a measure of economic performance.