A client in a business writing course asked if the abbreviations i.e. and e.g. were interchangeable. They are not. Each has a specific meaning and use.
- i.e. is the customary abbreviation for "that is." It is derived from the Latin term "id est."
- e.g. is the customary abbreviation for "for example." It is derived from the Latin phrase "exempli gratia."
- (So I don't have to worry about remembering the Latin derivations, I simply remember that example and e.g. both start with the letter e. E=example=e.g. Therefore, examples use e.g. while clarifications use i.e.)
e.g. in a sentence:
The marketing team will require only the basic presentation materials for the Atlanta trip (e.g., Product Benefits PowerPoint, Competitor Comparison Checklist). Be sure everyone receives full travel itineraries by tomorrow.
i.e. in a sentence:
We eliminated the Alexa shoe from our upcoming catalog after customer complaints alerted us of quality issues (i.e., the red ink was not colorfast). When you meet with department store managers, I recommend substituting the similar Daniella shoe.
- Only use these abbreviated forms e.g. and i.e. in more informal or expedient documents. It is always correct to simply write out, "for example," or "that is."
- Since these are abbreviations, they do require a period after each letter.
- All but one main style guide recommends a comma after use: i.e., and e.g.,