Scientist Rankings
Citation counts are a form of peer recognition and generally reflect the dependence of the scientific community on the work of individual scientists. It could be argued that highly cited scientists form the essential core of the scientific community. Many highly cited scientists have also received peer recognition in the form of honorific awards.

Institution Rankings
By aggregating publications and citations at the institutional level, we can measure the institutional output and prestige attributable to the affiliated researchers. Scientific research is performed within the context of an institution, and thus the recognition afforded the individual researchers affiliated with that institution is reflected in the prestige and reputation of the institution as a whole.

Country/Territory Rankings
Countries and territories vary in their level of scientific effort as measured by publication and citation activity. The distribution of effort is uneven, and dominated by the developed countries. The level of activity is roughly correlated with a country's GNP and other measures of economic output. Comparing countries or territories on a citations per paper basis can help correct for size (output) differences.

Journal Rankings
Journals vary widely in prestige, influence, and impact, and this is reflected in the citation counts to a journal. Essential Science Indicators provides a long-term citation ranking for journals. Consulting the Journal Citation Reports product (subscription required), published by Thomson Reuters, can make a comparison with short-term citation behavior.