@ican711nm,
Thanks, ican. It helps a little, but I think it stimulates more questions in my mind as well, than it answers. GDP as described is pretty much what I have always understood it to be, but I have never really tried to understand in great detail how it is calculated by various methods. I hope all do not mind if I attempt to summarize them here, and others can correct me if I am off track on any of this. Perhaps the Economy Thread would have been a better place to mention this subject, but since the issue is here, pardon me for posting this.
Here is what I gleaned from it. There are perhaps 3 different methods of determining GDP, or Gross Domestic Output. One would be the PRODUCT APPROACH, which sums the outputs of every class of enterprise to arrive at the total. I could not find any elaboration about this approach in the link, so I am unsure just how the data would be collected, and also how anything produced by the government would be included, if it is?
Another would be that of what is purchased or consumed is the "EXPENDITURE APPROACH," calculated as follows:
GDP = private consumption + gross investment + government spending + (exports − imports)
I immediately have some questions about the validity of this method, principally in regard to government spending. Government consumption or spending does not seem to be a good measure of anything valuable being produced and consumed. For example, we all know there is a tremendous amount of waste in how the government spends its money. And would the bailout of GM be included as part of this calculation for example? In contrast, private consumption seems like it would be a good measure of products and services having been produced that were consumed, but the purchasing of goods and services by government seems to me to be a very poor measure of the value of goods and services.
A third method in your link, for calculating GDP is apparently the "INCOME APPROACH." This approach apparently adds the following forms of income
1.Wages, salaries, and supplementary labour income
2.Corporate profits
3.Interest and miscellaneous investment income
4.Farmers’ income
5.Income from non-farm unincorporated businesses
These five income components sum to net domestic income at factor cost.
Two adjustments must be made to get GDP:
1.Indirect taxes minus subsidies are added to get from factor cost to market prices.
2.Depreciation (or capital consumption) is added to get from net domestic product to gross domestic product.
Similar questions as in the first approach would arise in my mind about this one. For example, how are social security benefits and taxes factored into this equation? Also, is government income or tax revenues factored in? They do not appear to, but I am not sure.
Obviously, this is a very complex subject, and one that a person could study in great depth for years and not completely be able to understand it thoroughly. I get the feeling that the result of any GDP calculation could be subject to at least some minor manipulation, and even perhaps major manipulation. And I was not even able to find in the article which method is used by our government to calculate GDP. It has to be in there somewhere I would think? I just hope the government has adequate control and monitor of the people involved in calculating all of this?