Do not ignore sources that seem contrary to your position or that offer arguments different from your own. Instead, use them to give voice to and to state potential objections to your argument before you counter them.
Anna Orlov, for example, cites conflicting evidence to acknowledge that readers may disagree with her position that online monitoring is bad for businesses.
On the one hand, computers and Internet access give employees powerful tools to carry out their jobs; on the other hand, the same technology offers constant temptations to avoid work. As a 2005 study by Salary.com and America Online indicates, the Internet ranked as the top choice among employees for ways of wasting time on the job; it beat talking with coworkers—the second most popular method—by a margin of nearly two to one (Frauenheim).
Related topic:
Counterarguments and opposing points of view