Chapter 8 - Quantitative research designs. After reading this chapter, you should 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 findings, and argue for your design choices; explain the benefits of experimental forms over quasi-experimental and descriptive forms;. | Chapter 8 Quantitative Research Designs 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 The Classical Experiment Researcher controls Selection of treatment & control groups – based on theory Random sample Random assignment of participants to conditions – ensures participants in each condition are equivalent before any treatment Manipulation checks Posttest Experimental Design Pretest-Posttest Experimental Design 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 Longitudinal Experimental Designs Multiple measurements of the dependent variable across time Time between measurements depends on the nature of the communication . | Chapter 8 Quantitative Research Designs 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 The Classical Experiment Researcher controls Selection of treatment & control groups – based on theory Random sample Random assignment of participants to conditions – ensures participants in each condition are equivalent before any treatment Manipulation checks Posttest Experimental Design Pretest-Posttest Experimental Design 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 Longitudinal Experimental Designs Multiple measurements of the dependent variable across time Time between measurements depends on the nature of the communication phenomenon studied Used for studying training effects or degree of retention Evaluating Experimental Design Strengths Researcher controls manipulation of IV and random assignment to condition 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 Quasi-Experiments Researcher relies on natural variation of independent variable Posttest, pretest-posttest, factorial, and longitudinal designs can be used Includes field experiments in which communication is studied in context Descriptive Designs Also called cross-sectional or non-experimental studies Researcher does not control manipulation of IV Participants not randomly assigned to conditions Predictor and criterion are better labels for IV and DV as they do not imply causality Researcher Effects and Procedural Bias Introduced in interaction with participants Similarity of .
