An indicator of journal impact that is based on calculating a journal's percentage of highly cited publications

The two most used citation impact indicators in the assessment of scientific journals are, nowadays, the impact factor and the h-index. However, both indicators are not field normalized (vary heavily depending on the scientific category) which makes them incomparable between categories. Furthermore, the impact factor is not robust to the presence of articles with a large number of citations, while the h-index depends on the journal size. These limitations are very important when comparing journals of different sizes and categories. An alternative citation impact indicator is the percentage of highly cited articles in a journal. This measure is field normalized (comparable between scientific categories), independent of the journal size and also robust to the presence of articles with a high number of citations. This paper empirically compares this indicator with the impact factor and the hindex, considering different time windows and citation percentiles (levels of citation for considering an article as highly cited compared to others in the same year and category).