Colons

Use a colon to introduce an idea, list or quotation. The clause before the colon must be a full sentence. If not, don’t use a colon.

An idea

Use the colon to introduce an idea that’s an explanation or continuation of the one before the colon.

There is one thing you need to know about statistics: they are fascinating.

Start the explanation or continuation with a capital letter if it’s a formal quote that’s a full sentence, or more than one sentence.

There is one thing you need to know about statistics: They are fascinating and I don’t know why anyone would think differently. Truly they have made my life better.

There is one thing you need to know about statistics: “A better thing has never been created,” said the Chief Statistician.

A list

Use a colon to introduce a list.

The statistics incorporate varied data: housing, schooling and population information.

Not

The statistics incorporate: housing, schooling and population information.

A quotation

Use a colon to introduce a quotation. The quotation should begin with a capital letter.

The judge stated: “You have suffered.”