Before revision:  Here, we use machine learning based on a 2-steps Gradient Boosting model,  to correct for the selection bias without requiring any strong assumption on the distribution. We use our method to estimate the Italian VAT Gap related to individual firms based on information gathered from administrative sources.
After revision:  Here, we use machine learning based on a 2-steps Gradient Boosting model, to correct for the selection bias which do not require any assumptions on the underlying data distribution. The 2-steps Gradient Boosting approach is used to estimate the Italian VAT Gap related to individual firms based on information gathered from administrative sources.