Semicolons before transitional phrases

The Quick Answer
A transitional phrase (e.g., however, as a result, consequently) will usually start a new sentence. However, if you would like a smoother transition between the first sentence and the one starting with the transitional phrase, you can use a semicolon before the transitional phrase. You cannot use a comma.

Semicolon before a Transitional Phrase

This point is closely related to the lesson Extending a Sentence with a Semicolon as it concerns merging two sentences to form one. However, in these examples, there is a short bridge between the first half and the second half of the sentence. The bridge is known as a transitional phrase. There is always a comma after a transitional phrase but not before.

A transitional phrase will usually start a new sentence, but if you would like a smoother transition than that afforded by a full stop / period, you can use a semicolon before a transitional phrase to merge the new sentence with the previous one.

Examples (transitional phrases shown in bold):
  • Everyone knows he is guilty; of course, it will never be proved.
    • (The transitional phrase of course acts like a bridge between the first half and the second half.)
  • Sarah's guest was turned away by the doorman; as a result, she left before the presentations.
    • (as a result – transitional phrase) 
  • Business is booming; for example, Siemens has made 10 orders since 4 o'clock.
    • (for example – transitional phrase)
  • I missed the early plane; however, I still made the meeting.
    • (however – transitional phrase)
  • The paper is stuck in the lift; consequently, we cannot finish the printing.
    • (consequently – transitional phrase)
  • She does not loathe chess, on the contrary, she quite likes it.
    • (The term on the contrary is a transitional phrase. You cannot merge two sentences into one with a comma. You must either start a new sentence or use a semicolon.)
  • My security guards are not trained in fire-fighting; therefore, we paged the fire service.

See Also

Commas after a transitional phrase Extend a sentence Using semicolons before conjunctions (and, or, but, etc.) Using semicolons in lists Using semicolons to extend a sentence