Peter Antonioni

As of late 2015, the U.S. GDP is more than $18 trillion, and projections are that it will grow by 2.7 percent to over $18.5 trillion before 2016 is over.In other words, if you add the value of all final sales recorded in the U.S. in one year it comes to more than $18 trillion. But note the qualifier final: To avoid double counting, economists count only the value of final goods produced, not intermediate goods.

Economics is often split into microeconomics and macroeconomics. Microeconomics is the study of individual and firm behavior, and macroeconomics is the study of the economy as a whole. Decades ago they were very different fields with different ways of doing things: Microeconomics stressed the importance of modeling individuals and firms as optimizing agents.

Economies run on people, firms, and governments requiring and buying things. A need exists (demand) that firms fulfill (supply). Students of microeconomics spend time learning about the behavior of supply and demand in individual markets. Students of macroeconomics are interested in the economy as a whole, so the emphasis is on aggregate (that is, total) demand for goods and services and aggregate (total) supply.

The interest rate is a special kind of price because it reflects exchanges through time. An annual interest rate of 5 percent says that in return for giving up $1,000 today, you can get $1,050 a year from now. Thus, $1,000 is the "price" of "buying" $1,050 in one year. To put it another way, you can get $1 in one year for a "price" of about 95 cents today.

Recall the Rule of 70. Remember, this rule is an easy way to calculate the time it takes something to double. If real gross domestic product (GDP) for instance grows at x percent per year, you divide x into 70 to find out how many years it will take for real GDP to double.Thus, if real GDP grows at 3 percent per year, it will double in 23 years and 4 months, double again in another 23 years and 4 months, and be 8 times what it was 70 years from the start.

In case you didn't know, the profit motive is powerful. Think about it. Hundreds of millions of people have invested trillions of dollars in pension funds, IRAs, and other assets to provide for their retirement or their children's education or for other reasons. The large banks, mutual funds, and other investment advisors compete for this business by trying to offer their investors a better return than their rivals.

The assumption (pretense) that underlies gross domestic product (GDP) — that you can think of the economy as just producing one, very multi-purpose good. Why do macroeconomists make this assumption?The simple answer is that they'd like to talk about "the economy" as parsimoniously as possible. If someone asks about the U.

Many economists think that the measures of inflation tend to overestimate the true increase in the cost of living. That is, if the inflation rate is quoted as being 3 percent, economists think that the true cost of living has actually increased by less than 3 percent.Here are some of the reasons why: The substitution effect: Inflation at 3 percent means that on average prices have increased by 3 percent.

Remember, you're imagining gross domestic product (GDP) as one single good. If that were really the case — if, say, you only produced oil — you'd have no trouble saying that if you produced 1,800 billion barrels of oil this year and next year, your real production hasn't increased, even if oil prices doubled from $10 to $20.