How Impact Factor Is Calculated

Impact Factor Formula:

\[ IF = \frac{\text{Citations in Year Y to Y-1,Y-2 Articles}}{\text{Citable Articles in Y-1,Y-2}} \]

Journal Impact Factor (IF):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What Is Impact Factor?

Impact Factor (IF) is a measure of the frequency with which the average article in a journal has been cited in a particular year. It is used to evaluate the relative importance of a journal within its field.

2. How Impact Factor Is Calculated

The Impact Factor is calculated using the formula:

\[ IF = \frac{\text{Citations in Year Y to Y-1,Y-2 Articles}}{\text{Citable Articles in Y-1,Y-2}} \]

Where:

\( Citations \) — Number of citations in the current year to articles published in the previous two years
\( Citable Articles \) — Number of citable articles published in the previous two years

Explanation: The Impact Factor provides a ratio between citations and recent citable items published, giving an indication of the journal's influence in the scientific community.

3. Importance of Impact Factor

Details: Impact Factor is widely used by researchers to identify influential journals in their field, by libraries for collection development, and by academic institutions for evaluation and promotion decisions.

4. Using the Calculator

Tips: Enter the number of citations received in the current year for articles published in the previous two years, and the total number of citable articles published in those two years. Both values must be valid positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is considered a good Impact Factor?
A: This varies by field. In some disciplines, an IF of 2-3 might be excellent, while in others, top journals may have IFs above 10 or even 20.

Q2: How often is Impact Factor updated?
A: Journal Impact Factors are typically updated annually and published in the Journal Citation Reports (JCR) by Clarivate Analytics.

Q3: What are the limitations of Impact Factor?
A: Impact Factor can be influenced by journal self-citations, varies significantly between disciplines, and doesn't reflect the quality of individual articles.

Q4: How does Impact Factor differ from other metrics?
A: Unlike CiteScore (which uses 3-year window) or h-index (which measures individual researcher impact), IF specifically uses a 2-year citation window for journal evaluation.

Q5: Can Impact Factor be manipulated?
A: Yes, through practices like coercive citation, publishing more review articles (which tend to be cited more), or excessive self-citation.