We are concerned with the unbiased estimation of a treatment effect in the context of non-experimental studies with grouped or multilevel data. When analyzing such data with this goal, practitioners typically include as many predictors (controls) as possible, in an attempt to satisfy ignorability of the treatment assignment. In the multilevel…

Climate change challenges governments to reduce emissions, and to gain support for such actions from their citizens. This can be in the form of taxation or legislation, or other forms of government interventions. In previous research, several instruments have been developed to capture attitudes towards the roles of markets and governments in the…