People rarely weigh every consideration at once. A frame works by making one cause, value, or consequence especially available when they form a judgment.

The cleanest test holds the underlying information constant and varies only the emphasis. If the messages contain different facts, the study cannot tell whether presentation or new information produced the response.

A genuine framing comparison holds the underlying policy or event constant while changing the consideration made prominent. Calling one proposal a tax relief measure and another a public-service cut may shift interpretation, but different reactions could also follow from different factual details. The evidence must isolate presentation from substantive information.

An experiment can isolate that difference. Two randomly assigned groups receive the same employment figures: one headline says that 94 percent of workers have jobs, while the other says that 6 percent remain unemployed. Different economic evaluations support a framing effect because the facts were equivalent and only the emphasis changed. Random assignment makes prior attitudes less likely to explain the gap.

Framing does not require a final opinion to reverse. It may change the reason a person gives, the value used, or the perceived cause of a problem while leaving the chosen policy unchanged. It also differs from making an issue more important or making it count more heavily in a judgment of a leader. The necessary safeguard is to ask what stayed constant. A message that adds a new cost is supplying new evidence, not merely presenting equivalent evidence differently. A persuasive framing study isolates the emphasis and then measures interpretation rather than simple attention or a changed policy preference.

Video lesson: Shaping Public Opinion: Crash Course Government and Politics #34