We obtain an LM test for the random effects probit model. In the natural parameterization of the model the necessary derivatives are identically zero under the null hypothesis. After a reparameterization, the feasible LM test is based on generalized residuals.

We explore practical methods of carrying out Lagrange Multiplier tests for variance components in two models in which the derivatives needed for the test are identically zero at the restricted estimates, the random effects probit model and the stochastic frontier model. The techniques are...