I am currently using the CausalImpact package for some research and in this context I need to know and be able to explain, how the posterior tail-area probability is calculated in order to reproduce that value for validation purposes. Does anyone know, how that value can be reproduced given the data and the estimation series provided by the model?
1 Answer
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The CausalImpact paper describes the calculation of the tail-area probability in detail (see section 2.3). There is probably no "easier" way to reproduce it than the actual implementation in the package...