This report, one of a series of externally commissioned ‘learning reviews’, aims to support the Start Fund’s definition of ‘under the radar’ crises and the application of the term in Start Fund processes. Following an analysis of a range of relevant tools designed to rank or simply catalogue emergencies, it was revealed that the term, ‘under the radar’ is not an industry standard, nor does it have a standard definition or application. In and of itself, therefore, it is insufficiently precise to add any real value in technical discussions. Each tool or index which defines a variant of ‘under the radar’ emergencies uses a definition or methodology which is fit for its respective purpose. For the Start Fund, specifying the explicit purpose for which the term is going to be applied is a critical consideration.