One of the most important economic stats used by economists is national income, which measures the size of an economy. It is important to note that national income is a measure of the output, expenditure and income of an economy. Economists can use various measures of national income to test hypotheses and build models of the economy. Governments, firms, and economists can also use these key indicators to forecast and predict changes in the economy which will allow them to implement adequate policies depending on the economic forecasts. Additionally, national income can be used to make comparisons over time and between other countries. For instance, national income statistics can be used to compare the income of the United Kingdom in 1975 and 2022, or they can be used to compare Sweden’s income with that of the UK.  Typically, there are 3 indicators of national income that are predominantly used.

The key measure of national income used in the United Kingdom is Gross Domestic Product (GDP). This is the total market value of all goods and services produced over a period of time. It is measured and market prices, which means that it is a measure of national income that includes the value of indirect taxes such as VAT. Calculating GDP includes adding together consumer spending, government spending, capital spending by businesses, and overall net exports.

• Consumption: The value of the consumption of goods and services acquired and consumed by the country’s households. This often accounts for the largest part of GDP.

• Government Spending: All consumption, investment, and payments made by the government for current usage.

• Capital Spending by Businesses: Spending on purchases of fixed assets and unsold stock by private businesses.

• Net Exports: This represents the country's difference between exports and imports, where a positive number bumps up the GDP as the country exports more than it imports, and vice versa.

Another measure of national income is the Gross National Product (GNP) which is the market value of goods and services produced over a period of time through the labour or property supplied by the citizens of a country both domestically and internationally.   

The difference between GDP and GNP is that GDP measures the value of goods and services produced within a country's borders, by citizens and non-citizens alike. GNP measures the value of goods and services produced by only a country's citizens both domestically and abroad. GDP is the most commonly used by global economies.