使用该命令后，stata提示sample may not include multiple panels，请问是什么原因呢

请问您知道根据help 如何给面板数据进行HP滤波吗？谢谢哈

我其他帖子或者回复里应该有命令和例子，您可以找找看

计算出来的结果怎么看吗？

对，help文档里说是年度取6.25，季度取1600，月度取129600，楼主是不是说错了？

谢谢！困扰好久终于找到办法了！

smooth(#) sets the smoothing parameter for the Hodrick–Prescott filter. By default, if the units of the time variable are set to daily, weekly, monthly, quarterly, half-yearly, or yearly, then the Ravn–Uhlig rule is used to set the smoothing parameter; otherwise, the default value is smooth(1600). The Ravn–Uhlig rule sets # to 1600*(p_q)^4, where p_q is the number of periods per quarter. The smoothing parameter must be greater than 0.