各位大神,处理面板数据,对样本进行豪斯曼检验确定回归时是使用固定效应还是随机效应模型,出来的结果中有这样一段提示:
note:the rank of the differenced variance matrix (6) does not equal the number of coefficients being tested (9); be sure this is what you expect, or there may be problems computing the test. Examine the output of your estimators for anything unexpected and possibly consider scaling your variables so that the coefficients are on a similar scale.
是什么意思呢?该做何处理?
谢谢指教!
谢谢stata大神!
所有变量都相同,但截面不完全相同,面板数据是非平衡面板。
您说的Pool OLS,我在stata guide查找,得到这个:pooled estimator. A pooled estimator ignores the longitudinal or panel aspect of a dataset and treats the observations as if they were cross-sectional.
这样会影响数据信息的使用吧?
此外该怎样检查是否适合做面板数据,还是做混合回归呢?
不好意思,麻烦了!多谢!