Teacher reflection is a key instrument for educational innovation. This paper describes and analyses a reflecxive experience on the affective suitability of a probabilities study process in secondary education. The objective of the research is to show the application of affective suitability indicators within a teaching experience, and how the are used to guide the teachers' reflection and to identify improvements and to explain did actical phenomena. The methodology qualitative, descriptive and interpretative, based on the application of affective suitability indicators to evaluate the level of adequacy to the context conditions and to identify significant did actical facts. The result is an application guide of affective suitability indicators to a study process of probability. Finally, after establishing the improvements to be implemented, the conclusions show the pertinence of this kind of reflective analysis as an instrument for teachers' innovation.