Question

Choosing effect size. Volker (2006) analyzed methods and approaches for reporting effect size in psychological research. In his assessment of estimates for effect size using the chi-square test, he wrote, Given that Cramer’s V is an extension of the coefficient, the values of effect size and Cramer’s V will be identical when a 2 X 2 (chi-square) is analyzed.

(a) Which coefficient is Volker (2006) referring to?

(b) Why are the two values of effect size identical when analyzing a 2 x 2 chi-square?

Answer 1

Solution:

Given that

Cramer’s V is an extension of the coefficient, the values of effect size and Cramer’s V will be identical when a 2 X 2 (chi-square) is analyzed.

a. The coefficient Volker (2006) is referring to is the phi coefficient.

b. For chi-square analyses, the effect sizes are phi (?) or Cramer's V, and therefore the values obtained should be identical from these two methods.