The gross domestic product is one of the chief ways a nation's economy is judged. As its name implies, the GDP is a total accounting of a nation's output, including all expenditures, revenues, and profits. Any average, like the average wage, plays no part in GDP, because GDP measures a complete output by a nation.

The Gross Domestic Product is very similar to Gross National Product except for one important distinction, the Gross National product takes into account foreign investments, whereas the Gross Domestic Product does not. For this reason most economic geographers consider the Gross National Product to be a slightly more useful statistic than the Gross Domestic Product.

The statistic of Purchasing Power Parity was created by geographers and economists to account for flaws in the Gross National Product - namely that the Gross National Product does not reflect how far the same amount of money goes in different countries around the world.

Bhutan is a small country in the Himalayan region of Asia that has eschewed the Gross National Product metric in favor of Gross National Happiness. The government contends that countries should be measured by how content and comfortable their citizens are rather than the aggregate sum of their riches, or industrial production.

The primary problem with the Gross National Product is that it presents the value of all economies based on the value of the US dollar. It ignores the fact that in different countries varying amounts of goods can be purchased with the same amount of money. For example, a house in New Jersey might cost you several hundred thousand dollars, in Lesotho it might cost you less than a thousand dollars. This basically means that an individual needs to earn less money to buy the same amount of goods. This distinction is reflected in Purchasing Power Parity (PPP).

The Gross National Product is one of the most widely used and quoted statistics in economic geography, particularly in popular parlance. It refers to the total monetary value, in US dollars, of all the goods, services, and investments produced by a country in a year.

In truth all of these are extremely strongly correlated with Gross National Product. But, income (obviously), life expectancy, and literacy rates are all more strongly correlated than is gender equity. This is because some countries, such as Italy in Europe, much of the Middle East, and Japan score far higher on measures like Gross National Product than they do on gender equity.

The Net Natural Product differs quite significantly from the other statistics used to measure relative economic development in a country because it takes into account the loss of natural resource caused by the productivity of the country. As such it is a natural favorite of environmental economic geographers.

The easiest way to figure this out is with vocabulary: primarily income vs. product. We know from the prefix in- that income deals with what is coming into the country. That leaves us with either Gross Domestic Product or Gross National Product. However, Gross National Product deals with the market value of the goods that have been produced by a country, not the actual amount of goods. Think of the two as quantitative vs. qualitative; GDP deals with how many goods were produced, while GNP deals with how much those same goods are worth. 

Stage 4 of demographic transition is the result of industrial and economic development and is characterized by a low and stabilized birth rate and a low and constant mortality rate. Countries that have undergone their industrial revolution and have adequate public health and education infrastructure such as Japan, the United States, and the United Kingdom are in Stage 4 of demographic transition.