Experimental Research
Studies administered under The Omnibus Project primarily fall under the rubric of experimental research. While some investigators have used TOP as a means of pretesting items for use in larger-scale surveys, most investigators have relied on the experimental method in their research.
Our emphasis on experimentation reflects an ongoing movement in the discipline of political science. The experimental approach has begun to permeate political science research, increasingly so in the last decade. Research universities across the country have established social science laboratories for experimental research, graduate students receive training in conducting and implementing their own experiments, and Time-Sharing Experiments in the Social Sciences (TESS) was developed to provide a peer-reviewed process by which experimentalists could place small modules on surveys administered to national samples of respondents.
Appropriate experimental designs offer researchers unparalleled control over stimuli, wide latitude in measurement, and, above all, internal validity: the ability to identify causal relationships between a stimulus and a response. Conducting experiments in a laboratory setting can ensure internal validity, due to the superior control over environmental conditions that laboratories offer, and laboratory settings may be preferred due to the wider range of questions, tests, and tasks that can be administered compared with studies in the field. For example, investigators in our laboratory have collected millisecond response latency data, have administered sophisticated audio-visual treatments, and have even had subjects play the dictator game. Although in the vast majority of our studies, subjects answer questions individually, recently, investigators have conducted multi-agent experiments as well, in which subjects are given the opportunity to consult with each other electronically as part of the study.
Subject Pool
Most of the laboratory studies conducted under TOP rely on convenience samples of undergraduate students at UC Davis. The subject pool is typically drawn from both lower-division and upper-division courses in the Department of Political Science (with occasional participation by other departments on campus). Students receive course credit for participating in the studies. Some TOP studies have also drawn from campus employees and residents of local towns (who are paid for their participation).
Mode of Interview
Studies under TOP use a self-administered computer-based survey mode. Occasionally, investigators have supplemented the computer-based mode with other tasks, including dictator games and paper-and-pencil open-ended responses.
For our computer-based instrumentation, we primarily use Inquisit v2.0, which allows for administration of close-ended and open-ended survey questions as well as presentation of images and video. A second software package, Z-tree, provides the infrastructure for multi-agent experiments in communication and decision-making.
Location
The studies take place in the Political Science Experimental Computer Lab and the Social Science Data Service Computer Lab. Click here for directions to the labs.
Human Subjects Protection
All studies conducted under TOP have been approved by the UC Davis Office of Research Institutional Review Board (IRB). All investigators, graduate student research assistants, and undergraduate research assistants have completed the required Human Subjects certification.