Methodological considerations on the use of the normalized impact in the Severo Ochoa and Maria de Maeztu programmes

In 2011, the research programmes for Support and accreditation of Severo Ochoa Centers of Excellence and Units of Excellence Maria de Maeztu were launched for the first time. Since then, these accreditations have become one of the axes of the Spanish scientific policy. In these years, (sic) 186 million have been distributed and 26 centers and 16 units have been accredited. At the bibliometric level, one of the most relevant evaluation criteria is the need for guarantor researchers to have a Normalized Impact of, at least, 1.5. In this work, we critically analyze the origin of this bibliometric indicator in the eighties, the variants that have been proposed and the limitations of its use in this national call. Finally we offer a series of practical recommendations for a more accurate use of the Normalized Impact indicator for evaluative purposes.