Scientist impact factor (SIF): a new metric for improving scientists’ evaluation?

Authors : Giuseppe Lippi, Camilla Mattiuzzi


The publication of scientific research is the mainstay for knowledge dissemination, but is also an essential criterion of scientists’ evaluation for recruiting funds and career progression.

Although the most widespread approach for evaluating scientists is currently based on the H-index, the total impact factor (IF) and the overall number of citations, these metrics are plagued by some well-known drawbacks. Therefore, with the aim to improve the process of scientists’ evaluation, we developed a new and potentially useful indicator of recent scientific output.


The new metric scientist impact factor (SIF) was calculated as all citations of articles published in the two years following the publication year of the articles, divided by the overall number of articles published in that year. The metrics was then tested by analyzing data of the 40 top scientists of the local University.


No correlation was found between SIF and H-index (r=0.15; P=0.367) or 2 years H-index (r=−0.01; P=0.933), whereas the H-Index and 2 years H-index values were found to be highly correlated (r=0.57; P<0.001). A highly significant correlation was also observed between the articles published in one year and the total number of citations to these articles in the two following years (r=0.62; P<0.001).


According to our data, the SIF may be a useful measure to complement current metrics for evaluating scientific output. Its use may be especially helpful for young scientists, wherein the SIF reflects the scientific output over the past two years thus increasing their chances to apply to and obtain competitive funding.