How to Choose Between I.E. and E.G.

Here’s a common question scientific writers ask themselves: “Is it i.e. or e.g.?” I’ve thought that same thing countless times. These two Latin abbreviations pop up all over the place, and they stand for exempli gratia (e.g.) and id est (i.e.). For those of you who aren’t fluent in dead languages (I’m right there with you), the translations are “for example” and “that is.” So if you’re introducing a list or giving some possible examples, use e.g. If you’re clarifying something or giving a definition, i.e. is what you want. How can we easily remember this difference?

---

Before I hammered the difference into my brain (figuratively), I remembered that e.g. starts with e, and so does “examples.” Mnemonics are everyone’s friend—choose what works for you!

Studying for my upcoming exam (i.e., the family medicine ITE) is taking up a lot of my free time. 

Studying for my upcoming exam (e.g., the family medicine ITE) is taking up a lot of my free time. 

In this example, I’m talking about my one upcoming exam. The appropriate abbreviation here would be the one that stands for “that is”: i.e. I’m not giving examples of multiple exams here, so e.g. would be incorrect.

Selecting e.g. or i.e. can also change your sentence’s meaning. Here’s how:

While studying for the internal medicine ITE, I took notes on the nonspecific clinical manifestations of cirrhosis (e.g., anorexia, weight loss, fatigue).

The insinuation here is that anorexia, weight loss, and fatigue are some examples of nonspecific clinical manifestations of cirrhosis. If anorexia, weight loss, and fatigue are the only nonspecific clinical manifestations of cirrhosis, i.e. would be correct.

While studying for the internal medicine ITE, I took notes on the nonspecific clinical manifestations of cirrhosis (i.e., anorexia, weight loss, fatigue).

Remember, this sentence is now saying “…that is, anorexia, weight loss, fatigue.” This subtle difference changes the sentence’s meaning by indicating that there are only three nonspecific clinical manifestations of cirrhosis rather than more than three.

---

Lastly, every style guide has its own preference for whether periods are included (is it eg or e.g.?) and whether to use a comma afterward. At Rosh Review, we like both the periods and the comma, which is the preferred style of many style guides. If you’re not following any specific style guide while you write, just make sure you choose a format and stay consistent.

---

Here are Laura’s most recent lessons:

Lesson 5: How to Easily Remember Affect vs Effect
Lesson 4: When Not to Use a Colon
Lesson 3: How (and Why) to Use Semicolons