Abstract: Disclosed is a technical solution to reduce latency in reader-retriever architectures of an open domain query response system. An example apparatus is to reduce latency in a retriever-reader architecture comprising at least one memory, machine readable instructions, and processor circuitry to at least one of instantiate or execute the machine readable instructions to identify a query, the query having data associated with the query, create a data array based on the data associated with the query, and deploy a machine learning model. The machine learning model is to assign a score to an index of the data array based on a likelihood that a response to the query exists in the index, determine an action to perform on the index based on a comparison of the score and a ranking threshold, and produce the response from the data array based on the action.