RM Unit 3 and 4

PES UNIVERSITY UNIT 3 - Research Designs

Overview

• Instructor: Ms. Namratha M, Assistant Professor, Department of Psychology

• Sessions Covered:

  • Experimental Designs (Pre-test/Post-test, Between-group, Factorial)

  • Non-experimental and quasi-experimental designs (time-series, equivalent time sample, non-equivalent control groups)

  • Mixed methods and mixed designs, case study, ex-post facto studies, surveys, developmental designs, correlational designs.

Experimental Designs

• Definition: A systematic sequence of steps designed to analyze objective data to infer cause-effect relationships between independent and dependent variables.

• Importance:

  • Essential for hypothesis testing.

  • Enables determination of cause-and-effect relationships.

  • Facilitates the selection of appropriate methodologies.

• Types:

  • True Experimental Design: Incorporates random assignment to groups, allowing for stronger causal inference.

  • Quasi-experimental Design: Involves manipulation of variables without random assignment.

Principals of Experimental Design

• Replication:

  • Duplication and deliberate repetition using nearly identical procedures across different subjects or settings.

• Randomization:

  • Random assignment of subjects to ensure each subject has an equal chance of being selected, which helps control for confounding variables.

• Local Control:

  • Balancing or grouping subjects to enhance the reliability of results.

Types of Experimental Designs

• Between Group Designs:

  • Randomized groups (2 or more groups assigned to different conditions).

  • Matched groups (subjects matched on certain characteristics).

  • Factorial designs (test multiple factors simultaneously).

• Within Group Designs:

  • Subjects undergo all conditions, allowing for internal comparison.

Non-experimental Designs

• Definition: Research lacking manipulation of independent variables; focuses on observing variables as they occur naturally.

• Types:

  • Correlational Research: Measures statistical relationships without manipulation.

  • Observational Research: Behavior observed without intervention.

• Importance: While it lacks causal conclusions, it provides substantial insights into relationships and trends.

Comparing Experimental and Nonexperimental Designs

• Experimental: Involves manipulation, internal validity emphasis.

• Nonexperimental: Observational, focuses on real-world applicability, external validity emphasis.

Quasi-experimental Designs

• Definition: Resembles experimental research but lacks true random assignment.

• Characteristics:

  • Manipulated independent variable.

  • Susceptible to confounding due to lack of random assignment.

• Types:

  • Time Series Design: Series of pretests and posttests on the same group.

  • Equivalent Time Sample: Repeated treatments with a single group.

  • Non-equivalent Control Group: Intact groups studied without reconstitution.

  • Ex Post Facto Research: Analyzing effects post events occurred, tracing back from effect to probable causes.

Mixed Methods Designs

• Definition: Combines qualitative and quantitative approaches for a more thorough understanding of research questions.

• Importance:

  • Enhances validity and reliability of findings.

  • Addresses complex phenomena from multiple perspectives.

• Types:

  • Convergent Parallel Design: Both data types collected simultaneously.

  • Explanatory Sequential Design: Quantitative data collection followed by qualitative.

  • Exploratory Sequential Design: Qualitative data informs quantitative.

Developmental Designs

• Definition: Examines the progress and changes over time in individuals or groups.

• Types:

  • Cross-sectional Designs: Different age participants tested at a single time; quick and cost-effective.

  • Longitudinal Designs: Same individuals tested multiple times over extended periods; provides insights into changes over time but time-consuming and expensive.

  • Sequential Designs: Combines elements of cross-sectional and longitudinal by assessing multiple age groups over time.

Advantages and Disadvantages

• Experimental Designs:

  • Advantages: Clear causal relationships, control over variables.

  • Disadvantages: May be artificial and less generalizable.

• Non-experimental Designs:

  • Advantages: High external validity, real-world relevance.

  • Disadvantages: Lower internal validity and inability to draw causal conclusions.

• Quasi-experimental Designs: Flexible but susceptible to confounding factors.

• Mixed-Methods: Comprehensive understanding but may be complex and resource-intensive.

Conclusion

• Understanding various research designs is crucial for proper methodology selection, enhancing research effectiveness, and deriving credible conclusions.