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Lecture Communication research - Chapter 8: Quantitative research designs

In this chapter students will be able to: Select and develop the appropriate research design for your hypotheses or research questions; understand the strengths and limitations of each design form as it relates to research fi ndings, and argue for your design choices; explain the benefi ts of experimental forms over quasi-experimental and descriptive forms; | Chapter 8 Quantitative Research Designs Copyright c 2001 The McGraw-Hill Companies, Inc. The Experimental Framework Used to determine causation Conducted in lab or other controlled setting To control for extraneous influences Independent variable is manipulated by researcher Participants randomly assigned to conditions or treatments Copyright c 2001 The McGraw-Hill Companies, Inc. The Classical Experiment Researcher controls Selection of treatment & control groups – based on theory Random assignment of participants to conditions – ensures participants in each condition are equivalent before any treatment Manipulation checks Copyright c 2001 The McGraw-Hill Companies, Inc. Posttest Experimental Design Copyright c 2001 The McGraw-Hill Companies, Inc. Pretest-Posttest Experimental Design Copyright c 2001 The McGraw-Hill Companies, Inc. Factorial Experimental Design Treatment groups based on two or more independent variables Dependent variable measured once after . | Chapter 8 Quantitative Research Designs Copyright c 2001 The McGraw-Hill Companies, Inc. The Experimental Framework Used to determine causation Conducted in lab or other controlled setting To control for extraneous influences Independent variable is manipulated by researcher Participants randomly assigned to conditions or treatments Copyright c 2001 The McGraw-Hill Companies, Inc. The Classical Experiment Researcher controls Selection of treatment & control groups – based on theory Random assignment of participants to conditions – ensures participants in each condition are equivalent before any treatment Manipulation checks Copyright c 2001 The McGraw-Hill Companies, Inc. Posttest Experimental Design Copyright c 2001 The McGraw-Hill Companies, Inc. Pretest-Posttest Experimental Design Copyright c 2001 The McGraw-Hill Companies, Inc. Factorial Experimental Design Treatment groups based on two or more independent variables Dependent variable measured once after treatment given Can test for main and interaction effects Copyright c 2001 The McGraw-Hill Companies, Inc. Longitudinal Experimental Designs Multiple measurements of the dependent variable Time between measurements depends on the nature of the communication phenomenon studied Used for studying training effects or degree of retention Copyright c 2001 The McGraw-Hill Companies, Inc. Evaluating Experimental Design Strengths Researcher controls manipulation of IV Assumes that any effect on DV is the cause of the IV Precision Limitations Not all communication can be studied using experiments Other external influence may be the cause of DV change May not reflect reality Copyright c 2001 The McGraw-Hill Companies, Inc. Quasi-Experiments Researcher relies on natural variation of independent variable Posttest, pretest-posttest, factorial, and longitudinal designs can be used Includes mock experiments, simulations, and field experiments Copyright c 2001 The McGraw-Hill Companies, .