Is the new citation-rank approach P100′ in bibliometrics really new?

•The percentile-based rating scale P100′ in terms of unique citation values is studied.•It is similar to standard percentile-based ratings in terms of citation frequencies.•A new indicator P100″ is introduced, but not seriously proposed.

The percentile-based rating scale P100 describes the citation impact in terms of the distribution of unique citation values. This approach has recently been refined by considering also the frequency of papers with the same citation counts. Here I compare the resulting P100′ with P100 for an empirical dataset and a simple fictitious model dataset. It is shown that P100′ is not much different from standard percentile-based ratings in terms of citation frequencies. A new indicator P100″ is introduced.