Media e ects research methodology, methods for studying media e ects. Experiment: gathering data under controlled conditions, requirements: Violent tv > aggressive behaviors: manipulation of an independent variable. Investigating people by asking questions directly: standardized questionnaire, contact methods of surgery. Face to face interviewing telephone, mail, emails and web surveys. Fax and text message polls: sampling: selection of respondents, random sample: everyone has an equal chance of being selected into the sample. Types of survey: cross-sectional surgery, surveying a single sample of some population at one time. Trend survey: uncovering over-time trends in a society, surveying di erent groups of individuals at multiple times. Interviewing those born in 1981 and afterward at multiple times. The individuals surveyed: are di erent individuals, but they belong to the same generational cohort, panel survey, uncovering changes occurring to individuals, surveying the same individuals at multiple times.