Multicollinearity is a common problem in econometrics. As explained in a previous post, multicollinearity arises when we have too few observations to precisely estimate the effects of two or more highly correlated variables on the dependent variable. This post tries to graphically illustrate the problem of multicollinearity using venn-diagrams. The venn-diagrams below all represent the following regression model Continue reading Graphically Illustrate Multicollinearity: Venn Diagram

# Omitted Variable Bias: An Example

This post is part of the series on the omitted variable bias and provides a simulation exercise that illustrates how omitting a relevant variable from your regression model biases the coefficients. The R code will be provided at the end. Continue reading Omitted Variable Bias: An Example

# The Problem of Multicollinearity

Multicollinearity or collinearity refers to a situation where two or more variables of a regression model are highly correlated. Because of the high correlation, it is difficult to disentangle the pure effect of one single explanatory variables on the dependent variable . From a mathematical point of view, multicollinearity only becomes an issue when we face perfect multicollinearity. That is, when we have identical variables in our regression model. Continue reading The Problem of Multicollinearity

# What is Total Factor Productivity (TFP)?

In growth theory, changes in output (GDP) are explained through changes of production factors, i.e. changes in labour or capital. Economists consider the residual, i.e. the part of changes in output that one cannot explain with changes of production factors, as total factor productivity (TFP) or technological change. In contrast to labour productivity, that relates output only to labour, total factor productivity states how efficiently an economy uses all its production factors. Continue reading What is Total Factor Productivity (TFP)?

# What is Labour Productivity?

Newspapers, and in particular economists frequently talk about labour productivity. Especially when commenting the current state of the economy, labour productivity is of central concern. This post will explain the concept of labour productivity and highlight its importance in the context of business cycle analysis. Continue reading What is Labour Productivity?

# Review: The Conscience of a Liberal

In *The Conscience of a Liberal*, Paul Krugman provides a compelling explanation for the recent increase of inequality in the United States. In contrast to the widely believed idea that is was globalization that caused the increase in inequality, he argues that Continue reading Review: The Conscience of a Liberal

# Review: Hillbilly Elegy

Hillbilly Elegy is a tale of social decay. In an absorbing and fascinating manner, J.D. Vance outlines different episodes of his life that go along with the social decline of the white middle-class in the Midwest. In an impressive fashion, Continue reading Review: Hillbilly Elegy