Residual household waste: from pay-per-bag to pay-per-kilogram. An evaluation study for Flanders

To be in line with the polluter-pays principle, an increasing number of Flemish municipalities have introduced a weight-based pricing system for residual household waste. Municipalities using this new pricing scheme are keen to ascribe decreasing waste production to the introduction of the new system. In order to evaluate the real impact of the weight-based pricing, an extension to the standard difference-in-differences evaluation techniques is proposed. The main idea is to use historical observations on waste production to determine which version of the difference-in-differences technique is most suitable to assess the impact of a policy action on waste quantities. The method is easy to apply, which makes it a very useful tool for both scientists and policy makers. Surprisingly, empirical results for Flanders indicate that, on average, municipalities using the weight-based system do not perform better than other municipalities.