Damage identification still remains a challenging but critical task in structural health monitoring field though many algorithms have been proposed in the past decades. Among them, methods based on elemental modal strain energy (MSE) change between pre- and post-damage are promising ones owing to their precision and robustness according to the studies conducted in the literature. Stubbs damage index method (SDIM) and Modal strain energy change ratio (MSECR) method are two representative approaches because of their different but original assumptions, having attracted considerable attention and thus been continuously improved by researchers. In this paper their efficiencies of damage localization and quantification in single- and multi- damage scenarios are compared through numerical study. Results show that, in general, MSECR method performs better than SDIM, especially in damage quantification. Theoretical discussion and improvements for SDIM are proposed and verified.© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.