Embodiments of an assessment method for processing a signal corresponding to a glucose concentration and performing a retrospective analysis includes the steps of: a) initiating a first trigger, wherein the first trigger defines the beginning of a segment of a continuous measurement of glucose concentration or define the first of a series of spot measurements of glucose concentration; b) collecting data of the continuous measurement or the series of spot measurements of glucose concentration to be analyzed, wherein the collected data relates to a glucose concentration excursion corresponding to a reaction to a relevant event such as a meal or physical activity; c) analyzing the collected data initiated by a second trigger, wherein the second trigger defines the end of the collected data to be analyzed, wherein a measure for a grading of the excursion is determined from the collected data, and d) displaying the result of the analysis.