dramatically. Measured changes in public tolerance for nonconformity have also been affected by changes in social context as the apparent Communist threat waxed and waned.
However, sometimes theory can help us to interpret otherwise confusing data. For example, the concept of a norm and the theories that come to us from social psychology can help us to understand why respondents sometimes lie to researchers about their "real" opinions. Theories such as cognitive dissonance can explain why it is that some people's opinions do not seem to go together. Theories about the public's lack of knowledge and the reasons for it offer alternative explanations for the same phenomenon. Theories about the role of the media, about the structure of government, and about the connections between public opinion and public policy may help us to understand why public faith in government is declining.
The relationship between theory and data is interdependent. Theories are developed based upon the research techniques and measurement instruments that exist or can be devised. Theories cannot be supported or refuted in the absence of data. Data cannot be effectively interpreted in the absence of theory. The drive to produce better ways of measuring public opinion and better theories to interpret it go hand in hand.