The article introduces a model for predicting interest rates based on two factors: the long-term rate and the difference between short-term and long-term rates. By using a specific mathematical process, the researchers derived equations to price bonds and interest rate derivatives. They found that including volatility in the long-term rate process improved predictions for medium- and long-term interest rates compared to a different model. Both models performed similarly for short-term rates, but considering volatility in the long-term rate process enhanced predictions for future interest rate movements.