<p>The assessment of scientific quality is a neccesity for the scientific community as well as those interesed in incentive and support policies of science. The present text has the aim to propose an aproximation to the assessment of scientific quality in which the systematic reviews play a fundamental role. Characteristics and limitations of the principal perspectives on assessment of science are discussed. Finally, it is exposed the own proposal and it is concluded that it satisfies the need for methods and criterio, both objective and rigurous, for the assessment of scientific products.</p>