Answer – Point-Bilingual Correlation (rρb) was useful when one of the variables was bifurcated. If both variables (X and Y) are bifurcated, Pearson’s product moment correlation is calculated as Phi Coefficient (Phi). Suppose you are interested in examining the relationship between job situation and marital status. Employment status is of two levels, employed and unemployed. Similarly, the marital status can be biennially taken at two levels: married and unmarried. Now we have both variables which are double-meaning. In such cases the correlation that is useful is the Phi coefficient (Phi).