Improving energy efficiency can reduce energy consumption, but it might also lead to increased energy use due to lower costs. A study on ASEAN countries from 1990-2014 found that short-term energy efficiency gains can actually result in more energy demand, while in the long run, there is only a partial rebound effect. The researchers used Stochastic Frontier Analysis to calculate energy efficiency and Generalized Methods of Moments to estimate energy efficiency elasticities. The findings suggest that while energy efficiency improvements can help reduce CO2 emissions, there is a complex relationship between energy efficiency and energy consumption in the ASEAN region.