The study looked at how well futures contracts can protect against price changes in commodities like corn and soybeans. They found that as futures contracts get closer to expiring, they become less effective at hedging against price changes. This is because the relationship between cash (spot) prices and futures prices changes as the contract nears its end. By analyzing data from 1990 to 2002, the researchers discovered that futures prices tend to follow a random pattern, while spot prices can be predicted. The effectiveness of hedging decreases as futures prices become more volatile, even before the contract expires. This means that using futures contracts to protect against price changes may not always work as expected.