TY - JOUR

T1 - Correcting coefficient alpha for correlated errors: Is alpha(K) a lower bound to reliability?

AU - Rae, Gordon

PY - 2006/1

Y1 - 2006/1

N2 - When errors of measurement are positively correlated, coefficient alpha may overestimate the ``true'' reliability of a composite. To reduce this inflation bias, Komaroff (1997) has proposed an adjusted alpha coefficient, alpha(K). This article shows that alpha(K) is only guaranteed to be a lower bound to reliability if the latter does not include correlated error. If one's definition of reliability includes correlated error, then an alternative adjusted alpha, alpha(R), is suggested, which will always be a lower bound.

AB - When errors of measurement are positively correlated, coefficient alpha may overestimate the ``true'' reliability of a composite. To reduce this inflation bias, Komaroff (1997) has proposed an adjusted alpha coefficient, alpha(K). This article shows that alpha(K) is only guaranteed to be a lower bound to reliability if the latter does not include correlated error. If one's definition of reliability includes correlated error, then an alternative adjusted alpha, alpha(R), is suggested, which will always be a lower bound.

U2 - 10.1177/0146621605280355

DO - 10.1177/0146621605280355

M3 - Article

VL - 30

SP - 56

EP - 59

JO - Applied Psychological Measurement

JF - Applied Psychological Measurement

SN - 0146-6216

IS - 1

ER -