tetrachoric {exametrika} | R Documentation |
Tetrachoric Correlation
Description
Tetrachoric Correlation is superior to the phi coefficient as a measure of the relation of an item pair. See Divgi, 1979; Olsson, 1979;Harris, 1988.
Usage
tetrachoric(x, y)
Arguments
x |
binary vector x |
y |
binary vector y |
Value
Returns a single numeric value of class "exametrika" representing the tetrachoric correlation coefficient between the two binary variables. The value ranges from -1 to 1, where:
1 indicates perfect positive correlation
-1 indicates perfect negative correlation
0 indicates no correlation
References
Divgi, D. R. (1979). Calculation of the tetrachoric correlation coefficient. Psychometrika, 44, 169–172.
Olsson, U. (1979). Maximum likelihood estimation of the polychoric correlation coefficient. Psychometrika,44, 443–460.
Harris, B. (1988). Tetrachoric correlation coefficient. In L. Kotz, & N. L. Johnson (Eds.), Encyclopedia of statistical sciences (Vol. 9, pp. 223–225). Wiley.