Combining reliability coefficients: toward reliability generalization of the conceptions of mathematics questionnaire

The combined coefficient alpha from studies reporting the reliability of scores using the Conceptions of Mathematics Questionnaire were computed. Five studies comprising 898 participants were evaluated. A test of differences among the independent coefficients alpha was statistically significant (chi42= 10.38, p = .04) for the Fragmented and (chi42 = 11.58, p = .02) for the Cohesive subscales. Post hoc comparisons showed the difference (F129,299 = 1.50, p=.003) was between Australia and Nigeria for the former and (F155,157 = 1.54, p= .004) between South Africa and the United States for the latter alpha values. A one-way analysis of variance, testing for homogeneity among means within each subscale, indicated that these were homogeneous because the measure of the strength of association accounted for 10% of variability. As reliability coefficients were from homogeneous samples and alpha values were not different, the combined reliability is the best estimate of the population reliability for each subscale.