Different journals have different reputation in the scientific community and in order to allow for evaluation of experts based on how prestigious journals their work get published in, the so called Journal Ranking is always presented next to the name of the journal in Monocl. There are multiple ranking systems for scientific journals and the one used in Monocl is called the SCIMago Journal Rank (SJR indicator). It is a measure of scientific influence of scholarly journals that accounts for both the number of citations received by a journal and the importance or prestige of the journals where such citations come from.
The SJR indicator is a variant of the eigenvector centrality measure used in network theory. Such measures establish the importance of a node in a network based on the principle that connections to high-scoring nodes contribute more to the score of the node. The SJR indicator, which is inspired by the PageRank algorithm, has been developed to be used in extremely large and heterogeneous journal citation networks. It is a size-independent indicator and its values order journals by their "average prestige per article" and can be used for journal comparisons in science evaluation processes.
The SJR indicator is a free journal metric which uses an algorithm similar to PageRank (by Google) and provides an alternative to the impact factor (IF). For more information, please checkout the official website.