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

"With the benefit of hindsight, we can say that we've had an overinvestment in residential housing over the past couple of years. This led to a buildup - a bubble, if you will - in housing prices, which finally burst. And that's led in many markets to falling housing prices, much slower buying of homes, in many cases foreclosures on people's homes and their mortgages. And this has caused troubles to many of those banks that have loaned money out to people to buy homes. Now, what's really behind this? I think that's what people are searching for. Were people being greedy? Were people making bad investment decisions? Well, I think you can point several fingers. I think, one, you can point to the Federal Reserve, which does have a lot of say over interest rates and the amount of credit in our economy, and the Federal Reserve was very lenient earlier this decade, pumped a lot of money into the economy, kept interest rates very low. So that sort of set the table for this investment in residential housing. Then we had different kinds of mortgages in the sense that we had a mortgage market that evolved where the institution that originated the mortgage was eventually separated from who actually owned that mortgage, so there was probably less attention to risk in that case, and that motivated, perhaps, lenders to take more risk. We had the role of those big government mortgage agencies, Fannie and Freddie, who, with implicit government backing, were out there encouraging an expansion of home ownership, which often meant lowering the levels of credit worthiness for borrowers. And then lastly, we had globalization. And globalization allowed foreign money to come pouring into the U.S., which also stoked the fires of this overinvestment in housing. So I think there are many players. We have many lesson to learn from this obviously so that we hopefully don't repeat it in the future."