Impact factor: The impact factor is a measure of the frequency with which the “average article” in a journal has been cited in a particular year. The JCR impact factor is basically a ratio between citations and recent citable items published. Thus, the impact factor of Journal X would be calculated by dividing the number of all current citations of source items published in Journal X during the previous two years by the number of articles Journal X published in those two years.

Immediacy Index is a measure of how quickly the “average article” in a specific journal is cited. A journal’s immediacy index considers citations made during the year in which the cited items were published. Thus, the immediacy index of Journal X would be calculated by diving the number of all current citations of current source items published in Journal X by the total number of articles Journal X published that year. An article published early in the year has a better chance of being cited than one published later in the year.

Cited half-life is the number of years, going back from the current year, which account for 50% of the total citations received by the cited journal in the current year.

Physics Impact Factors sorted by impact factor

Physics Impact Factors sorted alphabetically by journal name