Notes on Research Methodologies

Experimental Research

  • Causality

    • Establishing causality requires demonstrating a relationship between variables.

    • Covariation: Two variables must be related (e.g., when one changes, the other tends to change).

    • Temporal Precedence: Changes in the independent variable (IV) must occur before changes in the dependent variable (DV).

    • Elimination of Alternative Explanations: Rule out plausible third variables or confounds to assert true causality.

  • Key Features of Experimental Design

    • Control of Extraneous Variables: Prevent confounds to isolate cause and effect relationships.

    • Use of Random Assignment: Participants are randomly assigned to ensure group equality and prevent bias.

    • Measurement of Dependent Variable: Observe how the DV responds to changes in the IV.

  • Types of Designs

    • Single Factor Design: Study one IV with multiple levels.

    • Factorial Design: Study multiple IVs simultaneously to determine interaction effects.

  • Between and Within Subjects:

    • Between-Subjects Design: Different participants are used in each condition.

    • Within-Subjects Design: Same participants are used across all conditions.

  • Validity Types

    • Internal Validity: The extent to which the study can rule out alternative explanations for the observed effects.

    • External Validity: The ability to generalize findings to other contexts.

    • Construct Validity: Ensuring that the operational definitions of variables align with theoretical concepts.

    • Statistical Validity: Proper use of statistical techniques to analyze results.

Non-Experimental Designs

  • Definition of Non-Experimental Research: Studies where the IV is not manipulated; researchers measure variables as they naturally occur.

  • Types of Non-Experimental Designs

    • Correlational Research: Aim to find associations between variables without manipulation.

    • Types of correlations:

    • Positive Correlation: Both variables increase together.

    • Negative Correlation: One variable increases while the other decreases.

    • Zero/No Correlation: No clear relationship between variables.

  • Complex Correlational Methods: Include correlational matrices and partial correlations controlling for third variables.

Quasi-Experimental Designs

  • Definition: Designs resembling experimental research without random assignment.

  • Types of Quasi-Experimental Designs

    • One-Group Designs: Measure the same group pre and post intervention.

    • Nonequivalent Group Designs: Compare results between groups that are not randomly assigned.

    • Interrupted Time-Series Design: Set of measurements taken before and after an intervention over time.

Qualitative Research

  • Purpose: To understand meanings, experiences, and contexts in depth.

  • Methods

    • Interviews: One-on-one to explore in detail.

    • Focus Groups: Gather diverse perspectives on a topic.

    • Participant Observations: Engage with subjects in their natural environment.

  • Qualitative Data Analysis:

    • Use of Memos and Notes to capture insights.

    • Coding: Systematically classify data to form patterns.

    • Deductive vs. Inductive Coding: Based on existing theories vs. allowing themes to emerge from the data.

  • Trustworthiness

    • Assess findings’ applicability through transferability.

    • Reflexivity: Researchers acknowledge their influence on the research process.