Correlation measures in item analysis
Colin Cooper · British Journal of Mathematical and Statistical Psychology · 1982
Henrysson (1963) has criticized the procedure of correlating an item with the sum of the remaining n − 1 items on the grounds that the criterion is a function of the items selected for analysis. Worst case distortions of the point biserial correlations are examined, and it is concluded that for many data sets such effects are likely to be negligible. In such cases it is argued that the corrected coefficients proposed by Henrysson (1963) should be avoided because of their strong assumptions concerning the factorial homogeneity of the test items.