Appendix ΙΙ: Indicators
Table of Bibliometric Indicators used
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Number of publications |
The number of scientific publications is calculated on the basis of: | An indication of the volume of research output for: |
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Share of publications (%) |
It is calculated as a percentage of: | An indication for the participation of: |
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Percentage of cited publications (%) |
The percentage of publications that have received at least one citation. It is calculated using overlapping 5-year periods for the following units of analysis: | An indication for the levels of visibility / recognition of scientific publications produced by: |
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Number of citations |
The number of citations within a specific time period to articles published by the analysed unit during the same time period. It is calculated using overlapping 5-year periods on the following levels: | An indication of the influence and visibility of scientific publications produced by: |
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Share of citations (%) |
It is calculated using overlapping 5-year periods as the percentage of citations received by the publications of: | An indication for the influence and visibility of: |
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Citation impact |
The citation impact is the average number of citations per publication and is calculated as the ratio of the number of citations recorded for a specific time period to the total number of publications of the same time period. Calculations have been performed using overlapping 5-year periods. As this indicator does not take into account the variations of citation practices within the different scientific fields, it was only used for the calculation of the citation impact of all Greek scientific publications. |
An indication for the impact of publications. |
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Relative citation impact |
The relative citation impact compares the citations to publications per unit of analysis [e.g. Greece] in relation to the citations to publications within a certain frame of reference [e.g. the EU countries]. It is calculated as the ratio of the corresponding citation impacts. When the value of the relative citation impact is greater than 1, the publications of the analysed unit have a greater impact than those within the reference frame. The indicator does not take into account the variations of citation practices within the different scientific fields. In this study the relative citation impact was only used to establish Greece's place amongst the member countries of the EU and the OECD and was calculated as the ratio of the citation impact for all Greek publications to the citation impact for the countries of the EU and the OECD. |
With reference to all Greek publications in all scientific fields, comparison can be made between the impact of Greek publications and those of EU and OECD publications. |
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Field normalised citation score (abv: citation score) |
This indicator expresses the citation impact normalised according to subject field. It compares the average number of citations to the publications of an analysed unit to the average number of citations to international publications from the same year, in the same research field. The Field Normalised Citation Score or citation score is the key indicator used in this study to estimate the impact of the publications of an analyzed unit in relation to world. It was calculated using software particularly developed by EKT. The specific software permitted normalisation of the citation values on an individual article level on the basis of the distribution of publications over the 253 subject fields designated by NSI and NCR-Greece. When the value of the citation score is greater than 1, the publications of the analysed unit have a greater impact than the world average. In the study citation scores were calculated after normalisation for: |
An indication for the impact of publications taking into account differences in citation practices across scientific fields. The impact of publications relative to world is derived for: |
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| Number of top publications (P Top X%) |
It is the number of publications attributed to a unit that belongs to the X% most cited publications in the world from the same year, in the same subject field. The ranking was carried out based on the number of citations. The indicator was calculated for 5-year periods to the percentile levels 1%, 5%,10%, 25% and 50% [that is the number of publications that were ranked worldwide in the 1%, 5%, 10%, 25% and 50% most cited publications] on the following levels: |
An indication of the volume of high impact publications produced by: |
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| Percentile breakdown of top publications (Top X%) |
It is the share (%) of publications attributed to a unit that belong to the X% most cited publications in the world from the same year, in the same subject field. It is calculated at percentile levels of 1%, 5%, 10%, 25% and 50%. When the percentile breakdown of a unit is approximately that of the corresponding world breakdown (or surpasses it) 1%, 5%, 10%, 25% and 50%, then the performance of the unit is considered equal or above the world average. The indicator is calculated over time periods of five years: |
Comparison to the world average for percentile breakdown of top publications is made for: |
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