Hello!

I'm conducting a placebo test on a staggered DID, I randomly assign treatment firms and policy year to my sample firms, repeat that 500 times, and I obtain the following graph. I read some related literature, however, they seem to be vague about what is the threshold of passing/not passing a placebo test. I wonder whether the graph below could be accounted as passing the placebo test, and why or why not so. Thanks for any advice!

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