Correlation is important for measuring test validity, or the ability of a test to measure what it is intended to measure. It is intuitive that the scores on the test and the construct need to be correlated, or related. Correlation also is used to measure test reliability. Test reliability includes the degree to which a test is consistent over time and the degree to which the test items are consistent with each other. Thus, different administrations of the same test to the same individual should produce similar or related (correlated) scores. Correlation also has important implications for causality, but it is critical to understand that just because two things are correlated, there is no implication that one of them causes the other.
Keeping correlation in mind, think about SAT scores. These scores are frequently used to select students for admission to college and to predict college success. Consider the advantages and disadvantages of using test scores as part of an admissions selection process. Then consider whether this method would work equally well for all students, regardless of their background (e.g., cultural or socioeconomic). Similarly, a student’s choice of major, such as art, might affect the predictive ability of the SAT. Under such circumstances, would the correlation coefficient between two sets of scores still be relevant to the specific context? Can the test scores still be predictors of success in college? Do specific scores cause success in college?
To prepare for this Discussion, think of examples of misleading correlations and meaningful correlations. Also consider how you would explain the relationship between correlation and causation.
With these thoughts in mind:
Provide an example of a misleading correlation and an example of a meaningful correlation. Then explain the relationship between correlation and causation. Be specific and provide examples. Support your response using the Learning Resources and the current literature.
Be sure to support your postings and responses with specific references to the Learning Resources.
Resources
- Anastasi, A., & Urbina, S. (1997). Psychological testing(7th ed.). Upper Saddle River, NJ: Prentice Hall.
- Chapter 3, “Norms and the Meaning of Test Scores” (pp. 49–54)
- Cohen, J. (1990). Things I have learned (so far). American Psychologist, 45(12), 1304–1312.
Laureate Education, Inc. (Executive Producer). (2010). Normal curve interactive. Baltimore, MD:
Laureate Education, Inc. (Executive Producer). (2010). Two tailed curve. Baltimore, MD: Author.
