SAT: The Colon And The Dash

The Colon And The Dash: Left-hand Rule

Pugin, who is best known for his work in the Houses of Parliament, believed architecture was a moral force:  a reminder of the past glories of Greece and Rome.

Notice that the portion to the left of the colon makes complete sense.

“Pugin, who is best known for his work in the Houses of Parliament, believed architecture was a moral force.”

This is the left-hand rule for both colons and dashes.

The portion of the sentence to the left of the colon or dash should make complete sense on its own.

Whenever you come across a colon or dash in an answer choice, you need to apply this left-hand rule to check whether a colon or dash can work there.

Here’s another example.

We collected a dozen pieces each of: apples, oranges, and peaches.

The portion to the left of the colon does not make complete sense. It is what is called a sentence fragment or an incomplete sentence.

Therefore, neither the dash nor the colon will work here according to the left-hand rule.

For most questions on the test you will not have to choose between a colon and a dash. So simply applying the left-hand rule suffices. Here’s an example from the Official Practice Test 7.

The first thing many test takers do is look at the answer choices and panic. B and D seem to set up the dreaded colon vs dash situation.  But is it really?

The portion till identify, “Employers can also identify”, does NOT make complete sense on its own. It is a sentence fragment. It’s clear then that according to the left-hand rule we cannot have either a colon or a dash! So the question of deciding between the colon and the dash does not even arise!

The Colon And The Dash: Distinguishing Them On The SAT

That said, you should know further differences between the colon and the dash because there might be the rare question where you do have to distinguish between them. Here’s a table that makes it easier for you to distinguish between the colon and the dash. There is overlap between their usage because in many situations they are actually equivalent.

With the left hand rule and these examples, you are all set to understand and deal with colons and dashes on the Writing and Language section!

Happy Prepping!