Inferential Methods for the Tetrachoric Correlation Coefficient
The tetrachoric correlation describes the linear relation between two continuous variables that have each been measured on a dichotomous scale. The treatment of the point estimate, standard error, interval estimate, and sample size requirement for the tetrachoric correlation is cursory and incomplete in modern psychometric and behavioral statistics texts. A new and simple method of accurately approximating the tetrachoric correlation is introduced. The tetrachoric approximation is then used to derive a simple standard error, confidence interval, and sample size planning formula. The new confidence interval is shown to perform far better than the confidence interval computed by SAS. A method to improve the SAS confidence interval is proposed. All of the new results are computationally simple and are ideally suited for textbook and classroom presentations.
Bonett, Douglas G.; and Price, Robert M.. 2005. Inferential Methods for the Tetrachoric Correlation Coefficient. Journal of Educational and Behavioral Statistics. Vol.30(2). 213-225. https://doi.org/10.3102/10769986030002213 ISSN: 1076-9986