This is a study of media bias in reporting of collective action events. Media traces, such as newspaper stories and television news broadcasts, have become a common source of information for researchers who seek to understand the forms, intensity, duration and other attributes of public protest. But the wide suspicion that such media traces provide a non-random selection of the population of those events as well as a distorted description of their features has led to caution in exploiting the rich potential of these data sources. Understanding how media institutions select from the vast range of collective action events that are available to be covered and how they describe them requires independent sources of evidence about the population from which such events are selected. Knowledge of the characteristics of the population of events and the media samples of them enable the researcher to investigate the causal structure of both selection and description bias. Such knowledge can provide the evidence to model the bias in a way that can help collective action scholars dependent upon media traces to interpret their findings more appropriately than is currently possible. Generating such knowledge is the goal of this ongoing project. In this phase of the research, the investigators will: 1) expand the years of the selection bias analyses by gathering, in electronic form, National Park Service permit records for 1993-95; 2) code National Park Police demonstration after-reports for the same 1992-95 period in order to provide a parallel test of the selection bias analyses; 3) systematically observe two additional Washington, D.C. demonstrations; 4) electronically search media records for coverage of these and two earlier observed demonstrations, as well as all 1993-95 Washington demonstrations; 5) employ a systematic schema to code television network news coverage of the annual March for Life, 1973-95; 6) systematically analyze all crowd size controversies in Washington, D.C. for the last sev eral decades; and 7) coordinate comparative analyses across several collateral selection bias projects. The chief aim of this project is to evaluate the quality of media data and thus guide social scientists in their appropriate use, but it also will contribute to sociological theory about the sources of media bias. A wider practical benefit will be knowledge that can be used to evaluate the validity of information provided to policy makers and the general public through the mass media and some government agencies.
