Before revision:  The final answer returned to the user is decided with an accept-or-reject mechanism that combines multiple candidate answers by comparing the level of agreement between the retriever-reader and reader-retriever results .
After revision:  The final answer returned to the user is decided with an accept-or-reject mechanism that combines multiple candidate answers by comparing the level of agreement between the retriever-reader and reader-retriever results into one single answer by examining the consistency between the two components .