A country’s total wealth includes everything it has accumulated from the past.
Its income or national output, however, is what is produced during the current year.
==Accumulated wealth== and current output are both important, in different ways, for indicating how much is available for different purposes, such as maintaining or improving the people’s standard of living or for carrying out the functions of ==government==, ==business==, or other institutions.
National output during a year can be measured in a number of ways, such as ==GDP== and ==GNP==.
Gross Domestic Product (GDP): Measures national output by summing all goods and services produced within a nation’s borders.
Gross National Product (GNP): the sum total of all the goods and services produced by the country’s people, wherever they or their resources may be located.
The real distinction that must be made is between both these measures of national output during a given year—a flow of ==real income==—versus the accumulated stock of wealth as of a given time.
Just as national income does not refer to money or other ==paper assets==, so national wealth does not consist of these pieces of paper either, but of the real goods and services that money can buy.
Sometimes ==national output== or ==national wealth== is added up by using the money prices of the moment, but most serious long-run studies measure output and wealth in real terms, taking into account price changes over time. terms, taking into account price changes over time.
Over a period of generations, the goods and services which constitute national output change so much that ==statistical comparisons== can become practically meaningless, because they are comparing apples and oranges.
A further complication in comparisons over time is that attempts to measure real income depend on statistical adjustments which have a ==built-in inflationary bias.==
==Real wages== are simply money wages adjusted for the cost of living, as measured by the consumer price index, but if that index is ==biased upward==, then that means that real wage statistics are ==biased downward==.
The same problems which apply when comparing a given country’s output over time can also apply when comparing the output of two very different countries at the same time.
One of the usual ways of making ==international comparisons== is to compare the total money value of outputs in one country versus another, however, this gets us into other complications created by official ==exchange rates== between their respective ==currencies==, which may or may not reflect the actual purchasing power of those currencies.
Consumer Price Index (CPI): Measures ==inflation== from the average change in ==prices== over time that consumers pay for a grouping of goods and services
GDP per Capita: Measure indicating national ==prosperity== based on ==economic growth==
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