Publishing papers in high profile journals is a milestone for any academic researchers. For up and coming researchers, the process of actually finding reputable journals to publish in can be a difficult process. We’ve written about the steps that one can take to do this. 

Today, we are delving into one of the most important factors that determine the quality of a journal and the work it publishes. Let’s get right to it! 


What is a journal’s “impact factor”? 

An impact factor (IP) or a journal impact factor (JIP) is numeric by which the academic community measures the quality of a journal. Let’s take a closer look into it.

One of the ways to measure the value of a scientific paper or a journal is to evaluate how many times it has been cited in newer works.This is precisely what the impact factor does: it is a way to rank journals within a specific field to see which of them has the most influence over future research? 

The impact factor calculated was designed by the Institute for Scientific Information (ISI), and has been in use since 1975.  

How is the impact factor calculated? 

It’s important to have a solid system of calculation to ensure that the impact factor truly reflects the status that a journal has within the field that it works in. 

The impact factor of a journal is calculated by comparing the number of citations credited to a journal and the number of papers that it has published the previous two years. 

ISI defines a publication as “items that are classed as ‘article’, ‘review’ or ‘proceedings papers’ in the Web of Science (WoS) database. 

So, the formula goes:

IMPACT FACTOR = Citations in Year X / Publications in Year X-1 + Publications in Year X-2


How does this actually play out? Let’s see. 

Let’s suppose that a journal was cited 5,000 times in 2019, and published 836 and 575 papers in 2018 and 2017 respectively. 

So the impact factor is 5,000 divided by 1,411, which is 3.543

IMPACT FACTOR = 5000 / 836 + 575 

= 5000/1411

= 3.543


Unsurprisingly, a journal calculates its first impact factor score two years into publishing. Sometimes, they also choose to calculate impact factors for longer periods of time. For example, a five-year impact factor, which calculates the number of citations in year “x” against all the articles published in the five years before that.


Hope this was a helpful first guide to impact factors. Subscribe to PaperTrue’s Resource Center for more explainers about academic writing and the publication process.