Bibliometrics uses quantitative methods to study scientific publications. These methods are based on the amount of publications and the number of citations they have received.
The most common bibliometric indicators (e.g. numbers of publications and citations, h-index (Fig. 1), impact factor (Fig. 2)) are presented here.
Bibliometrics can be used e.g. for:
- Evaluating performance of individual researchers
- Positioning and benchmarking of countries, cities, research groups
- Citation analysis, scientific impact and excellence assessment
- Network and collaboration mapping
Fig. 1. As an example of the bibliometric indicators, h-index for a researcher is determined by arranging a list of publications in a descending order according to the number of citations and finding the ordinal number of publications that has been cited at least as many times as how large the ordinal number is. h-Index 5 means that the researcher has five publications that have been cited at least five times.
Fig. 2. Journal impact factor, for example, for the year 2017 is calculated by tallying up the citations to articles published in the journal in the two previous years (2016+2015), and this sum is divided by the number of articles published in the journal within the same period of time. If a journal’s impact factor is 4.5, it means that for each article published in the journal has been cited an average of 4.5 times during the two years prior to the impact factor year.