A numerical approach for computing standard
errors (SEs) of a linear equating is described. In
the proposed approach, the first partial derivatives
of the equating function needed to compute the
SEs are derived numerically. Thus, the difficulty of
deriving the analytical formulas of the partial
derivatives for a complicated equating method is
avoided. The numerical and analytical approaches
were compared using the Tucker equating method.
The SEs derived numerically were found to be
indistinguishable from the SEs derived analytically.
In a computer simulation of the numerical
approach using the Levine equating method, the
SEs based on the normality assumption were found
to be less accurate than those derived without the
normality assumption when the score distributions
were skewed. Index terms: common-item design,
Levine equating method, linear equating, standard
error of equating, Tucker equating method.