A review of research methods COMM Fall 2007 Nan Yu

Quantitative research methods

Surveys Advantages Disadvantages Surveys show correlational evidence (i.e., patterns of variables in a large population). Survey instruments rely solely on self-reported measures. Low reliability. Surveys are very good at discerning attitudes, beliefs and perceptions They are not good for studying behavior, emotions, etc. Have high external validity (real-world situation, large samples) They can hardly prove causation. Random error is high.

Survey design  Cross-sectional studies observation at one point of time  Longitudinal studies observation over time establish patterns and shifts over time

Types Longitudinal Study TrendCohortPanel different samples Samples are subgroups from a same population. same samples A cohort is a group of people who share a common characteristic or experience within a defined time period. (e.g. class of 1997, people that were born between 1990 to ) Sample size might be different over time (people moved, died…). Require probability sampling from the same population, otherwise you can not compare the data collected at different times.

Types of surveys Watt, J. H., & van den Berg, S. A. (2002). Research methods for communication science. Needham Heights, MA: Allyn and Bacon, p.278, p. 290

Sampling error and sample size Sample size The greater the sample size, the less the sampling error.

Problematic questions  What are problems with the following questions? “ What is your income? ” “ Do you jog regularly? ” “ Does your college offer master or doctoral programs? ” What is your total family’s household income before taxes during last year? How many times do you job per week? Double-barreled questions

Techniques of asking sensitive questions Goal: to increase truthful answers to sensitive questions:  “Foot in the door” The researcher builds some trust and respondents are more comfortable towards the end with the researcher and the procedures. Place sensitive questions (e.g. demographic questions) at the end.

Experiments A true experiment has 4 characteristics:  Manipulated independent variables  Random assignment  Experimental conditions (other than manipulated IVs) are held constant or as similar as possible.  Dependant variabless are systematically measured.

Internal vs. External Validity of Experimental Studies When a true experiment (with full control by the researcher) is carried out properly, the study has high internal validity. Changes in the DV were probably caused by (not merely related to or correlated with) the treatment. However, experiments have lower external validity.  What is the reason for this?

Factorial design DV: Liking toward the picture A 2X2 factorial design 4 conditions

Random Assignment (cont.) Why we need random assignment? Because we want to make sure that the differences between groups after they were exposed to different levels of the IV are due to the IV effect on the DV, and not to the differences between groups.

Random Assignment (cont.) Treatment ATreatment B experimenter Flipping a coin Pull names from a thoroughly shaken box. Random numbers table Participants come in random orders, and experimenter randomly assign them to treatment A or treatment B.

Steps in a true (full) experiment study Formulate a hypothesis or a research question. Manipulate IV(s) (stimulus). Pretest the stimulus Recruit participants Present to the participants a cover story Randomly assign participants to a treatment group or to the control group. Introduce treatment or intervention Measure the dependent variable (s) Debriefing

Main effect and interaction

Content Analysis Systematic study of communication contents in an objective and quantitative manner. The researcher uses objective and systematic counting and recording procedures to produce a quantitative description of the symbolic content in a text. Why do we need content analysis?

Applications of content analysis Describing communication content Testing hypothesis of message characteristics Assessing the image of particular groups in society. Comparing media content to “real world” Establishing starting point for media effects research, (e.g. cultivation and agenda setting)

Content Analysis The content refers to words, meanings, pictures, symbols, ideas, themes, any message that can be communicated, etc. The text refers to anything written, visual, or spoken that serves as a medium for communication (e.g., books, newspapers and newspaper articles, advertisements, speeches, official documents, movies, musical lyrics, photographs, etc.)

Coding and measurement Measurement (coding) in content analysis uses structured observation: systematic, careful observation based on written rules. The rules explain how to categorize and classify the observations (i.e., units). Written rules are important in content analysis, as they improve the reliability and make the replication possible.

Intercoder reliability In order to improve the reliability and eliminate differences in judgments, researchers train and use more than one coder. If they agree most of the time on what unit should be placed in which category, the reliability is high. This type of reliability is called intercoder or interrater reliability.

Qualitative Research Methods

When are qualitative methods most useful? When the research objective is:  To interpret, illuminate, illustrate  To understand how or why  To describe previously unstudied processes or situations  To get in-depth, detailed information  To understand context  To learn about subjects who are few or hard to reach  To capture experience University of Illinois, Champaign-Urbana

Research Questions Research questions that seek to describe lived experience, explain meaning or offer rich, thick description should be answered using qualitative methods.

Sampling Generally always purposive  Definition: A goal of reaching a pre-defined group Different types of purposive sampling:  Snowball, extreme case, stratified and opportunistic No need for random sampling: the goal of qualitative research is not to generalize but to explain  Example: We need people who have attended a Penn State football game in order to study the experiences at a Penn State football game

Two types of qualitative methods Focus groups (p.206)  Researcher (facilitator, moderator) is part of the communication with a selected group of participants, but in control of questions being asked and the environment. In-depth interview  One-on-one interviews,  Researcher observe the communication verbally and nonverbally  More freedom in constructing questions

Advantages and limitations of focus group Richness in the data  Explanatory and descriptive Inexpensive and quick Quality of the research largely depends on the facilitator’s ability to direct the discussion. Some participants may monopolizing the talk. Low external validity

Advantages and limitations In-depth interviews Story-telling Richness of the data Take long time to complete Personal perspectives Limited ability to generalize

ExperimentSurvey Content Analysis Focus Group In-depth interview Rationale Sampling Instrument Study procedure Analysis /conclusion Overview

Control In-depth interviewfocus group survey experiment Less rigorousMost rigorous