Answer: the value as opposed to the price of an item; environmental degradation; total output and income.
Explanation:
While it is true that GDP calculations omit such things as the value as opposed to the price of an item and environmental degradation, it is still a useful way to measure total output and income.
Gross Domestic Product is a means of measuring economic performance over a given period(usually a year). It works by adding up the final value of the goods and services produced in a country in that given period and thus can show the total output and income in a country.
Sadly however, it has some shortcomings. One of those is that it uses the prices of goods not their actual value. Another is that it does not take into account important factors such as environmental degradation which if added, would reduce GDP because the environment on average suffers negatively from production.