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Non experimental research (1)

Non-Experimental Research Overview

  • Focus on Non-Experimental Research: The document discusses various aspects of non-experimental research, emphasizing its significance in scenarios where experimental design is not feasible.

When Non-Experimental Research is Preferred

  • Single Variable Focus: Research questions relating to a single variable rather than relationships between two (e.g., accuracy of first impressions).

  • Non-Causal Statistical Relationships: Examining correlations between variables without assuming causation (e.g., verbal vs. mathematical intelligence correlation).

  • Unmanipulable Independent Variables: Situations where independent variables cannot be manipulated due to practical or ethical constraints (e.g., effects of hippocampus damage on memory).

  • Broad Exploratory Questions: Research about specific experiences (e.g., experiences of working mothers with depression).

Types of Non-Experimental Research

  • Observational Studies:

    • Focus on qualitative research and ethnography studies.

  • Correlational Research:

    • Types include survey research, archival data, and naturalistic observation.

  • Quasi-Experiments:

    • Include case-control studies, cohort studies, and natural experiments.

Correlational Research Explained

  • Definition: Investigates relationships between variables without manipulation by the researcher.

  • Correlation Strength: Indicates both the direction and strength of relationships between variables.

Understanding Correlation Strength (Cohen, 1988)

  • Correlation Size Indicators:

    • Negative Correlation:

      • Small: -0.10 to -0.29

      • Medium: -0.30 to -0.49

      • Large: -0.50 to -1.00

    • Positive Correlation:

      • Small: 0.10 to 0.29

      • Medium: 0.30 to 0.49

      • Large: 0.50 to 1.00

Practical Example of Correlation

  • Example: Exploring the correlation between height and basketball dunking ability illustrates application in sports research.

Types of Correlational Research

  • Naturalistic Observation: Study behavior in natural environments without interference.

  • Survey Method: Collect data through questionnaires.

  • Archival Research: Analyze existing data or documents.

Archival Research Insights

  • Case Study: In Ancient Rome, a positive correlation noted between urban treasury coins and femur lengths of adult men.

Survey Research Insights

  • Vaccine Hesitancy Case: High correlation between vaccine hesitancy and political affiliation, identifying trends across various states.

Economic Freedom and Living Standards

  • Context: High economic freedom generally correlates with higher GDP per capita, showcasing the interrelations between economy and governance.

Longitudinal Research and IQ

  • The Flynn Effect: Documenting increases in mean IQ scores across diverse global regions over time.

Mathematically Precocious Youth Study Cohorts

  • Cohorts: Different cohorts identified based on SAT scores showcasing the talent pool in mathematically gifted students.

Limitations of Case-Control Studies

  • Bias Types: Includes selection bias, survival bias, and recall bias which can impact the study's validity.

  • Control Group Matching: Difficulty in ensuring both control and experimental groups are comparable.

Prospective Cohort Study Limitations

  • Challenges: Include difficulties in studying uncommon diseases, diseases with long latency periods, and multiple exposures.

Natural Experiments and Endogeneity

  • Endogeneity Problem: This occurs when predictor variables correlate with dependent variables due to unmeasured factors, potentially leading to biased results.

  • Omitted Variable Bias: Leaving out relevant variables which can misattribute effects in research.

Differences-in-Differences Analysis

  • Observing Trends: Evaluating changes in outcome trends for groups over time to determine intervention effects.