How to Determine Whether Two Correlation Coefficients are Significant

A test is available that will evaluate the significance of differences between two correlation coefficients in two samples.

The outcome of this test depends on two factors:

  • The size of the raw difference between the two coefficients

  • The size of the samples and on the size of the coefficients themselves

Consistent with the previously discussed principle, the larger the sample size, the smaller the effect that can be proven significant in that sample. In general, due to the fact that the reliability of the correlation coefficient increases with its absolute value, relatively small differences between large correlation coefficients can be significant.

For example, a difference of .10 between two correlations may not be significant if the two coefficients are .15 and .25, although in the same sample, the same difference of .10 can be highly significant if the two coefficients are .80 and .90.