i.e. versus e.g.

November 19, 2015

Dr. Jennifer C van Velkinburgh, Filipodia Publishing


In this post, we will tackle a seemingly small editing item, but one which is a source of confusion for many authors and editors: the use of i.e. versus e.g.


Let’s first take a look at the following sentence:

There are many well-established techniques for analyzing proteins, i.e., electrophoresis.


Is this sentence correct?


No. The Latin abbreviation e.g. should have been used instead of i.e.




The correct usage of two abbreviations is often obscured by the general abandonment of Latin in everyday communication. To understand the correct usage of Latin abbreviations, one must first understand the meaning of the abbreviated terms. The abbreviation i.e. stands for “id est”, which translates to “that is” or “in other words” and should be used to paraphrase a preceding statement in a more clear way. The abbreviation e.g. stands for “exempli gratia”, which translates to “for example” and this phrase should be used to give a list of examples.


Thus, for the sentence above, if we use i.e., we are telling the reader that electrophoresis is the only technique, which contradicts the preceding statement of “many well established techniques”.


Moreover, a comma is often recommended to be used after the i.e. and e.g. when used in the middle of a sentence, and it is recommended to not use the additional abbreviated Latin term “etc.” at the end of the list of examples (since e.g. indicates that the items represent a non-finite list).