The article discusses a method called Data Envelopment Analysis (DEA) that helps measure how efficiently businesses or processes are running. In this study, researchers focused on using DEA to evaluate environmental efficiency, especially when dealing with harmful outputs like greenhouse gases. They introduced a new approach that looks at both good and bad outputs to identify the least efficient practices. By analyzing real data from paper production, they found that this method can provide a more accurate assessment of overall efficiency, including environmental impact.