The significance of rank difference coefficients of correlation

The coefficients of rank difference correlation that are barely significant at six different levels of significance are given forN's of 2 to 30. Most of the values were obtained by translation of Olds' tables of probabilities for various values of d². Comparison of these data with those obtained by four other methods indicates that one method yields values more appropriate than those obtained from Olds' data for coefficients significant at the .01 level forN's from 11 to 25. This method also provides a convenient means of obtaining approximate values of coefficients significant at the .01 level forN's above 30. Need for caution in evaluating the significance of coefficients obtained from data involving tie rankings is indicated. The article concludes with recommendations as to choice of methods of determining the significance of rank difference coefficients.