KR–21 provides a lower limit for the computed value of KR–20. KR–20 is equivalent to coefficient alpha when a test is composed of dichotomous items scored 0 or 1. Therefore, KR–21 coefficients, computed from simple summary statistics, can be used in cases in which journal authors do not provide the test score reliability. Use of KR–21 in these cases will provide the reader with a lower limit for the value of KR–20.
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References
1.
AllenM. J.YenW. M. (1979) Introduction to measurement theory.Monterey, CA: Brooks/Cole.
2.
FeldtL. S.BrennanR. L. (1989) Reliability. In LinnR. H. (Ed.), Educational measurement. American Counsel on Education. New York: Macmillan.
3.
KuderG. F.RichardsonM. W. (1937) The theory of the estimation of test reliability. Psychometrika, 151–160.
