![](/olcweb/styles/shared/spacer.gif) | ![How to Design and Evaluate Research in Education Book Cover](/sites/dl/free/0072532491/title/fw_sm.gif) How to Design and Evaluate Research in Education, 5/e Jack R. Fraenkel,
San Francisco State University Norman E. Wallen,
San Francisco State University
Correlational Research
Main PointsThe Nature of Correlational Research - The major characteristic of correlational research is seeking out associations among variables.
Purposes of Correlational Research - Correlational studies are carried out either to help explain important human behaviors or to predict likely outcomes.
- If a relationship of sufficient magnitude exists between two variables, it becomes possible to predict a score on either variable if a score on the other variable is known.
- The variable that is used to make the prediction is called the predictor variable.
- The variable about which the prediction is made is called the criterion variable.
- Both scatterplots and regression lines are used in correlational studies to predict a score on a criterion variable.
- A predicted score is never exact. As a result, researchers calculate an index of prediction error, which is known as the "standard error of estimate."
Complex Correlational Techniques - Multiple regression is a technique that enables a researcher to determine a correlation between a criterion variable and the best combination of two or more predictor variables.
- The coefficient of multiple correlation (R) indicates the strength of the correlation between the combination of the predictor variables and the criterion variable.
- The value of a prediction equation depends on whether it predicts successfully with a new group of individuals.
- When the criterion variable is categorical rather than quantitative, discriminant function analysis (rather than multiple regression) must be used.
- Factor analysis is a technique that allows a researcher to determine whether many variables can be described by a few factors.
- Path analysis is a technique used to test a theory about the possibility of causal connections among three or more variables.
Basic Steps in Correlational Research - These include, as in most research, selecting a problem, choosing a sample, selecting or developing instruments, determining procedures, collecting and analyzing data, and interpreting results.
Correlation Coefficients and Their Meaning - The meaning of a given correlation coefficient depends on how it is applied.
- Correlation coefficients below .35 show only a slight relationship between variables.
- Correlations between .40 and .60 may have theoretical and/or practical value depending on the context.
- Only when a correlation of .65 or higher is obtained can reasonably accurate predictions be made.
- Correlations over .85 indicate a very strong relationship between the variables correlated.
Evaluating Threats to Internal Validity in Correlational Research - Threats to the internal validity of correlational studies include subject characteristics, location, instrument decay, data collection, and testing.
- Results of correlational studies must always be interpreted with caution, because they may suggest, but they cannot establish, causation.
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