The harmonization of data issued from daily clinical activity is a continuous challenge. Compositional systems such as SNOMED CT allow the representation of most of clinical data. However, specific conceptual domains remain challenging. One of those remaining challenges is the representation of clinical scales. This work proposes a pragmatic, internally validated solution to accurately represent clinical scales in a large consortium of public hospitals. Based on expert consensus, we developed a methodology that, even if institution-specific, allows to capture the complexity of clinical scales.