The purpose of this chapter is to try to explain the growth in GDP. The models in this chapter are very different from the rest of the models in this book as they use only the production function and factors of production to explain growth.
An important macroeconomic variable is the total amount of labor that is used in a certain time period. The amount of labor and the amount of capital are important explanatory variables for production and GDP. Another reason for the importance of the amount of labor is that it is related to the unemployment rate – a macroeconomic variable which is clearly important.
The Keynesian model
In this chapter we will look at the Keynesian cross model. This model is a simple version of what we call the ”complete Keynesian model” or simply the Keynesian model. The Keynesian model has as its origin the writings of John Maynard Keynes in the 1930s, particularly the book ”The general theory of Employment, Interest, and Money”.
The neo-classical synthesis is a synthesis of the classical model and the Keynesian model. In short, it states that the Keynesian model is correct in the short run while the classical analysis is correct in the long run. Let us consider a concrete example. According to the Keynesian model, an increase in G will increase Y and reduce unemployment.
We have now reached the second part of this book. The first interest rate was a description of the macroeconomic variables and institutions. In the second part, we will analyze how these variables fit together and present models that explain the main macroeconomic variables.