A self-selected listener opinion poll, also called SLOP, is an unscientific poll that is conducted by broadcast media (television stations and radio stations) to engage their audiences by providing them an opportunity to register their opinion about some topic that the station believes has current news value. Typically two local telephone numbers are broadcast for listeners to call to register their opinion on a topic. One number might be for those who agree with the issue, and the other might be for those who disagree. For example, a question might be to indicate whether a listener agrees or disagrees that “the mayor should fire the police commissioner.“

Because the people who choose to call in do not represent a known target population, the findings from such ...