It is widely accepted that innovative initiatives need to scale if they are to have sustainable impact. However, the widespread use of the 'scaling' notion stands in sharp contrast with an apparent lack of knowledge how to be successful at it: For instance, a study on over 3'000 start-ups found that 70% of start-ups attempt scaling without being properly prepared for it (Marmer et al. 2011). We thus suggest that scaling represents a formidable, under-researched management challenge with important practical implications for start-up survival, growth and, ultimately, job and societal welfare creation. We contribute a study, which aims at convergence by, first, reviewing and synthesizing the emerging literature, deriving a scaling framework and, then, by comparing prior theoretical ideas and propositions with initial results from a significant largescale data collection effort on scaling from specialized start-up coaches as well as directly from the firms.