多期DID平行检验，tvdiff命令的 leads通过，但time-trend没通过怎么办

请教各位老师，在采用平行DID时，tvdiff命令的默认lead通过检验，但time-trend没通过怎么办？还可以用平行DID吗？并且我的模型加入时间趋势，发现时间趋势并不显著，还需要考虑它吗？
[CODE]

• Example generated by -dataex-. To install: ssc install dataex
  clear
  input float(lnsp madynamic profit lev) double knowledge float(lns rd)
  1.609438 0 4.8941 40.916 .11420000344514847 20.966864 .
  0 0 .9096 41.9497 .1225999966263771 20.999556 .
  .6931472 0 1.5252 46.5688 .1116 21.095165 .
  .6931472 0 2.6897 46.7801 .0814 21.40688 .
  1.3862944 0 3.3193 48.7414 .0716 21.52864 2.21
  1.94591 0 2.7067 48.6291 .0691 21.55847 2.21
  1.3862944 0 3.2729 53.7108 .04960000142455101 21.6357 1.74
  .6931472 0 3.7503 55.9038 .043299999088048935 21.74129 2.45
  0 0 3.0894 57.0549 .04490000009536743 21.82454 2.92
  .6931472 0 3.7042 62.7174 .03819999843835831 21.99292 2.73
  0 0 2.616 70.3921 .11760000139474869 20.64575 5.63
  0 0 7.1632 70.5722 .11969999969005585 20.68328 5.63
  0 0 5.8235 73.0624 .1059 20.789003 5.63
  0 0 18.5548 70.3759 .0873 20.894827 5.63
  0 0 30.2027 61.5809 .0578 20.90041 3.9
  0 0 18.4419 58.4694 .0578 20.95858 4.82
  0 0 12.121 56.0119 .05779999867081642 20.94105 4.73
  0 0 6.4818 58.9444 .05290000140666962 21.001337 4.29
  .6931472 0 11.3496 52.9828 .052799999713897705 20.999044 3.32
  0 0 20.6415 36.9631 .04259999841451645 20.963575 3.64
  0 0 28.454 21.69 .035599999129772186 22.003567 .
  0 0 37.5627 17.7752 .03460000082850456 22.164604 .
  0 0 40.7253 19.0484 .0285 22.3958 .
  0 0 35.7805 14.9746 .0308 22.51164 .
  0 0 40.2427 19.2 .031 22.73281 2.86
  --more--
  使用命令为tvdiff lnsp madynamic profit lev knowledge lns rd, model(fe) pre(3) post(3) vce(robust) test_tt graph save_graph(mygraph)，madynamic类似于交乘项
  

Tvdiff 不靠谱

请问楼主解决了这个问题吗

请问楼主解决了这个问题了吗？谢谢！

为啥我用tvdiff直接no observations

请问楼主解决了吗？我也遇到了同样的问题。

三年又一年 发表于 2021-5-23 21:38
为啥我用tvdiff直接no observations

我现在也是，用tvdiff显示no observations，你怎么解决哒！

请问楼主解决了这个问题吗，很痛苦