The aim of the present work is to introduce the methodology used to carry out a diagnostic of the system of evaluation in learning for Mathematics I (subject of the first year in the Facultad de Bioquímica, Química y Farmacia of the Universidad Nacional of Tucumán in Argentina) This diagnostic was based on a model of alternative evaluation of learning, designed on the basis of criteria resulting from constructivist pedagogical currents and on the basis of methodological principles for the qualitative and quantitative paradigms in socioeducational research. The criteria stated in this model led to the formulation of the hypothesis: “the evaluation of learning in the subject is enhanced with a reductionistic and disintegrated conception of the processes of teaching and learning”. In order to contrast it, surveys were designed which were applied to students in years 2001 and 2003 and to teachers in year 2001, and a study was carried out on the items of summative evaluation of the subject based on the principles of evaluation standards of the National Council of Teachers of Mathematics. The sources of information were chosen by attending to the characteristics of the context of work and the limitations which conditioned the investigation. A technique was designed to analyze the open and close questions of the surveys and to study the items of the exams. This facilitated the elaboration of a system of categories with which the diagnostic was implemented. The methodological design adopted and the sources used were adequate to reach the aims proposed in the study. Besides, they provided the means to find solid argumentations to contrast the hypotheses of work.