Since the early 2000s, theorizing on incremental institutional change has made inroads in comparativehistorical analysis. In particular, the ideas, concepts, and theory introduced by Kathleen Thelen and hercollaborators have been widely adopted by scholars. These scholars are not, however, univocally positiveabout the theory. Three main critiques have been plaguing the theory since its early days: the concepts itbuilds on lack clarity, the model of agency it uses is too static, and the theory lacks analytical poweroverall. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis method,this article presents a meta-analysis of the peer-reviewed empirical literature from 2005 to 2015 thatapplies this theory. It seeks to better understand the reach of the critiques expressed, as this may providea starting point for improvement. It finds considerable quantitative support for the critiques, anduncovers an additional problematic issue: the tendency for concept stretching and concept proliferationby scholars seeking to overcome the shortcomings of the theory. Paradoxically, concept stretching andproliferation only further reduce the analytical power of the theory. The article concludes withsuggestions for improvement of the development and application of the theory.