Cronbach is a research finding that has brought many questions to the table to prove its
existence and be able to work with it in the future. This proofing is brought about by several
misconceptions about the ideas of the score reliability and lack of understanding of the original
concept. A shared mistake is that reliability score is a representative of a test or a dimensional
tool; though, reliability score is a characteristic of results (Tavakol and Dennick, 2011).
Cronbach’s alpha is defined as a measure of uniformity, as revealed by how items from a
group are closely related. It measures the scale reliability. Cronbach’s alpha states that when a
measure of internal consistency is high, it does not mean that the unit measured is
unidimensional. If the scale in question is unidimensional, then it must be supported with
evidence, which includes analyses of tests to estimate the scale’s consistency (Green et al.,
1997). Therefore, the alpha is regarded as a coefficient of reliability, which is inscribed as a
function of the calculated sum of test components and average intercorrelation among the tested
elements. The formula below is a standardised Cronbach’s alpha formulation of its coefficient
(Tavakol and Dennick, 2011).
From the coefficient formula above, N is an equal number of tested items, c-bar is
average inter-component correlation covariance amongst the elements as well as v-bar which is
the average variance. Over the years, Cronbach’s alpha has undergone a lot of rectification and
improvements to come up with a standardised formula for calculating its coefficient. The
improvement action led to many researcher’s interventions to prove the properties of the alpha
Underpinnings of Cronbach’s Alpha3
and rectify the misconceptions. The research bore result which included some ratio variance
formula development. The examples being adapted from Thompson (2003) and Henson (2001).
Underpinnings of Cronbach’s Alpha4
Green, S.B., Lissitz, R.W. and Mulaik, S.A., 1977. Limitations of coefficient alpha as an index
of test unidimensionality1. Educational and Psychological Measurement, 37(4), pp.827-
Henson, R.K., 2001. Understanding internal consistency reliability estimates: A conceptual
primer on coefficient alpha. Measurement and evaluation in counselling and
development, 34(3), p.177.
Tavakol, M. and Dennick, R., 2011. Making sense of Cronbach's alpha. International journal of
medical education, 2, p.53.
Thompson, B., 2003. Understanding reliability and coefficient alpha. Score reliability:
Contemporary thinking on reliability issues, pp.3-23.