The purpose of this study is to analyze the development of the evaluations process by those professionals who carry out evaluations with regard to functional diversity. This evaluative research is conducted with a mixed approach that combines qualitative and quantitative data collection and data analysis techniques. The sample consists of 108 professionals from 31 institutions dedicated to adults with intellectual disabilities, and from five special educational centers. The sample selection, the design, and the interpretation of results are based on the assumption that the academic profiles of professionals in these institutions are heterogeneous, and that they perform complementary functions of intervention and evaluation. Results show a wide variety of professional functions of both diagnosis and process and product evaluation, and of planning, intervention and communications of results, highlighting evaluations by multiple professionals. Some generic difficulties (lack of time, information, resources, etc.) and specific difficulties from the studied context (difficulty of providing individual attention, poor administration support, etc.) are noted. For these professionals, evaluation is mainly used to reflect on their work, to self-evaluate for progress, and possibly to further commit to the people involved. Results are discussed, and possible actions to counter the expressed difficulties are proposed