Bornmann L, Marx W, Barth A. The normalization of citation counts based on classification systems. Publications 2013;1(2):78-86
This study describes an ideal solution for the normalization of citation impact: in a first step, the reference set for the publication in question is collated by means of a classification scheme, where every publication is associated with a single principal research field or subfield entry and a publication year. In a second step, percentiles of citation counts are calculated for this set, and are then used to assign a normalized citation impact score to the publication in question. The major advantages of this approach are the application of a systematic high-quality classification system, the simplicity of the procedure, and the balance of fairness of the resulting citation counts.