摘要：In spite of the great enthusiasm and ample diffusion that have waked up the portfolios as a innovating resource in the assessment and education of the teaching staff, an analysis of their sense must be carried out to avoid their indiscriminate and little critical use. This article reviews the origins and educative foundations of teaching portfolios, as well as some studies that report their potentiality as a resource of authentic assessment and reflection on the own identity and educative practice of preservice teachers. Also, criticism and precautionary notes with respect to their use are reviewed, mainly when its application is tried as large-scale standardized instrument. The potential of Portfolios resides in the promotion of teacher's reflective self-evaluation and in the possibility of driving a change in the culture of assessment in the educative institutions. At the same time, the great risk consists of the proliferation of an exclusively technical and biased glance, centered in the instruments, with little theoretical ground and empirical investigation.
