Causal-Comparative Research
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This document discusses causal-comparative research, which aims to identify cause-and-effect relationships between groups by comparing two or more groups that differ on some independent variable. The key points covered are: 1) Causal-comparative research examines pre-existing differences between groups and attempts to determine the cause of those differences, unlike experimental research which manipulates variables. 2) It is useful for studying variables that cannot be manipulated, to inform decisions, and provide a basis for future experimental research. 3) Procedures involve selecting groups that differ on an independent variable, collecting background data, and comparing groups on a dependent variable while controlling for extraneous variables.
Causal-Comparative Research
- 2. Topics Discussed in this Chapter The definition of causal-comparative research The purpose of causal-comparative research Comparisons with other designs Design issues and procedures Control Data analysis and interpretation
- 3. Definition of Causal- Comparative Research A form of study that tries to identify and determine the cause and effects of relationship between two or more groups. It is a common form of design in education researches.
- 4. The purpose of Causal- Comparative Research Attempts to determine the cause for preexisting differences in groups of individuals The alleged cause and effect have already occurred Orientations
- 5. Similarities and Differences to Correlational Research Correlational No attempt to understand cause and effect Two variables, one is a predictor and one a criterion One group Involves relationships Causal comparative Attempt to understand cause and effect At least one independent variable (i.e., purported cause) and one dependent variable (i.e., purported effect) Two or more groups Involves comparisons
- 6. The similarities Both lack manipulation Both require caution in interpreting results Both can support subsequent experimental research
- 7. Comparison to Experimental Research Experimental Causal group comparisons Individuals randomly assigned to treatment groups Independent variable manipulated by the researcher Causal comparative Group comparisons – but not causal Individuals already in groups before research begins Independent variable not manipulated Cannot Should not Is not
- 8. Examples of Non-Manipulated Variables Age Sex Ethnicity Learning style Socioeconomic status Parental educational level Family environment Preschool attendance Type of school Organismic var Personality var Family-related var School related var
- 9. The Value of Causal- Comparative Research Permits the investigation of variables that cannot or should not be manipulated Can inform decisions Results can lead to experimental studies that establish causality Very cost effective to conduct
- 10. Procedures of Causal- Comparative Research Select two groups that differ on some independent variable The independent variable must be clearly operationally defined Randomly sample subjects from each of the two groups Collect background information on subjects to help determine the equality of the groups Compare groups on the dependent variable
- 11. Control of Extraneous Variables Lack of randomization, manipulation, and control are all weaknesses of causal comparative designs Three ways to control extraneous variables - Matching – pair-wise matching of subjects on a variable likely to influence performance - Comparing homogeneous groups – create groups that are similar on an important extraneous variable - Analysis of covariance (ANCOVA)
- 12. Data Analysis A. Descriptive statistics Central tendency Mean Median Mode Variation Standard deviation B. Inferential statistics t test ANOVA ANCOVA Chi square
- 13. Interpretation of Data Difficulty establishing cause and effect requires caution in interpreting results Causality and alternative explanations