Baltagi, Badi; Song, Seuck Heun; Jung, Byoung Cheol - In: Econometric Reviews 21 (2002) 2, pp. 167-187
This paper derives several Lagrange Multiplier tests for the unbalanced nested error component model. Economic data with a natural nested grouping include firms grouped by industry; or students grouped by schools. The LM tests derived include the joint test for both effects as well as the test...