The article compares two models to see how productivity growth in agriculture affects the economy. One model focuses only on agriculture and shows a lot of positive effects when productivity increases, like more money for people and businesses. The other model looks at the whole economy and finds that the benefits are spread out differently, with some areas gaining more than others. Overall, the model that looks at just agriculture predicts a bigger boost to the economy when things get better on farms, while the other model suggests a more uneven impact on different parts of the economy.