The Truth About Consequences and Corrections

Restriction of range occurs whenever design or circumstances abbreviate the values of one or both variables being correlated. Range restriction has an impact on score validity, score reliability, and statistical power. As a result, researchers need a more sophisticated concept of the relationship between.variance and correlation than the simple assumption that when variance goes down, correlations decrease. The shape of the distribution and selection procedures also influence whether restriction of range increases, decreases, or does not affect correlation. (Contains 16 references.) (SLD) Reproductions supplied by EDRS are the best that can be made from the original document. Restriction of Range 1 Running head: RESTRICTION OF RANGE: THE TRUTH. Restriction of Range: The Truth About Consequences and Corrections Deborah A. Weber Texas A&M University 77843-4225 PERMISSION TO REPRODUCE AND DISSEMINATE THIS MATERIAL HAS BEEN GRANTED BY ) A. ilJeJtoer 1 TO THE EDUCATIONAL RESOURCES INFORMATION CENTER (ERIC) U.S. DEPARTMENT OF EDUCATION Office of Educational Research and Improvement EDUCATIONAL RESOURCES INFORMATION CENTER (ERIC) This document has been reproduced as received from the person or organization originating it. Minor changes have been made to improve reproduction quality. ° Points of view or opinions stated in this document do not necessarily represent official OER1 position or policy. Paper presented at the annual meeting of the Southwest Educational Research Association, New Orleans, February 1-3, 2001. 2 BEST COPY AVAILABLE Restriction of Range 2 Abstract Range restriction impacts score validity, score reliability, and statistical power. Thus, researchers need a more sophisticated concept of the relationship between variance and correlation than simply assuming that when variance goes down, correlations decrease. The shape of the distribution and selection procedures also influence whether restriction of range increases, decreases, or does not affect correlation.Range restriction impacts score validity, score reliability, and statistical power. Thus, researchers need a more sophisticated concept of the relationship between variance and correlation than simply assuming that when variance goes down, correlations decrease. The shape of the distribution and selection procedures also influence whether restriction of range increases, decreases, or does not affect correlation.