The Subject Sameness Index: a new scientometric indicator

Abstract

Background
A variety of scientometric indicators exists for quantitative and qualitative evaluation of scientific output. Each of these indicators has its own strengths and limitations, and the search for more correct ones is still ongoing. This study proposes and evaluates a new scientometric indicator, Subject Sameness Index (SSI).
Method
This cross-sectional study was conducted over a six-year period (2005-2010). We analysed all papers published by researchers of Babol University of Medical Science (BUMS), who were first authors with at least two papers listed in Web of Science (WoS) during the six-year period. A special tool was developed for data collection. The ratio of the same (repeated) or synonym keywords to all keywords listed by researchers in their papers was analysed for estimating ‘subject sameness’.
Results
We retrieved 90 papers of BUMS researchers. These researchers were first authors, with 25 of them having at least 2 papers (67 in total). Of these, 11 papers had at least one repeated or synonym keyword. In these papers there were 300 keywords in total, with 21 repeated or synonymous keywords (7% of all the keywords were repeated). Regression analysis showed a reverse linear relationship between the number of published papers and the number of repeated or synonym keywords (R = -0.963, P = 0.037).
Conclusion
Quantity of publications, citations and their combinations are not always appropriate indicators of the quality of scientific work. Low level of the subject sameness may indicate a researcher’s dispersed scientific activity. The new indicator, SSI, may add important information of interest to research administrators and science editors