When should a block quotation be used?
When a writer chooses to include a long quotation—one that takes up four or more lines of text—it must be set off as a free standing block. As with any quotation a writer employs as evidence, the original text should contain relevant and compelling ideas that are expressed in vivid and concise language.
Block quotations should be used sparingly in longer essays and articles (multiple pages) and rarely in shorter works (1,500 words or less). Lengthy, wordy quotations should never be used simply to fill pages when the writer has little to say about the topic or issue.
How should a block quotation be formatted?
- A block quotation is introduced with an informative, full-sentence signal phrase that ends with a colon.
- The entire free standing block of the quoted material is indented 1” from the left margin (10 spaces) and is double-spaced throughout.
- The first line of the quotation is not indented more than the following lines, unless two or more paragraphs are quoted.
- Quotation marks are not added at the beginning or end of the quotation.
- The end punctuation appears at the end of the last sentence in the quotation, not after the page number; no additional punctuation appears after the parenthesis.
- Example: These results deserve further investigation. (23)
- Add a concluding sentence or sentences after the block quotation to complete the paragraph.
Let’s look at an example:
In their investigation of the way the human mind deals with multitasking, Salvucci and Taatgen determined that driving is an act that requires drivers to engage in a variety of simultaneous subtasks; when drivers choose to add interaction with an electronic device to an already complex activity, the new demands on their minds can distract them from their primary task:
The heavy cognitive workload of driving suggests that any secondary task has the potential to affect driver behavior. Any concurrent task would necessarily involve procedural steps and thus, whether large or small, create additional cognitive workload. At the same time, not all secondary tasks are created equal, and we would expect some tasks to interfere with driving more than others. Not surprisingly, tasks involving significant visual demand have the greatest potential for negative effects on driver performance. (108) 
Thus, the researchers determined that the use of electronic devices—such as cell phones—while driving can possibly place enough additional demands on the drivers’ mental capacity to compromise their ability to operate a vehicle safely.
For more information about using quotations, see also:
 Salvucci, Dario D., and Niels A. Taatgen. Multitasking Mind. Oxford: Oxford UP, 2011. eBook Collection (EBSCOhost). Web. 20 Feb. 2012.