Experimental Design
We have designed a randomized control trial (RCT) in collaboration with the Danish Tax Agency, which is the main agency within the Danish tax authorities. The focus of the project is exclusively on auditing applications for refunds of dividend withholding tax. As the refunds are a way of committing tax fraud, the main purpose of the audits is to combat fraud by preventing and discouraging it. Currently, the tax agency conducts various types of audits, varying in depth and scope.
Our RCT design consists of selecting claims for different types of audit based on the predicted probability of non-compliance. To select claims based on the probability of non-compliance, we constructed machine learning models using historical data on refund applications, including information about the applications and the audit outcomes (i.e. compliant or non-compliant). We use one of these models to predict the probability of non-compliance for unprocessed claims.