Testing for correlation in error‐component models
误差成分模型中的相关性检验
Summary This paper concerns linear models for grouped data with group‐specific effects. We construct a portmanteau test for the null of no within‐group correlation beyond that induced by the group‐specific effect. The approach allows for heteroskedasticity and is applicable to models with exogenous, predetermined, or endogenous regressors. The test can be implemented as soon as three observations per group are available and is applicable to unbalanced data. A test with such…