Dr. Mike Walden, North Carolina Cooperative Extension economist in the College of Agriculture and Life Sciences at N.C. State University, responds:

"Of course assets are investments -- ... anything from stocks to bonds to gold to homes. And economists believe that the value of any asset is anchored by that asset's fundamentals. So if you are talking about a stock, ultimately what determines the value of a stock is whether that company is making a profit and how profitable it is.

"If you are talking about homes, a value of a home is going to be determined by the supply of homes, the demand for homes and the number of people and the income of those people wanting to buy homes. That is going to determine home values.

"We say that asset bubbles exist when the asset values become detached from those fundamentals -- that is to say, you can't explain the value of the asset by these economic fundamentals -- particularly, they have gotten too high.

"And we saw that, for example, with technology stocks in the late '90s where they didn't have any association with the underlying profitability of the company. And we also saw it with housing values earlier in the 2000 decade.

"And the problem with asset bubbles, of course, is they can be pricked. They can come down. And we saw that also with the tech bust, and we saw that with the housing bust.

"However ... it is very difficult at the time -- at the time -- to know if you have an asset bubble. This is something the government is now struggling with, particularly the Federal Reserve."