An approach is provided in which an information handing system converts source evidence extracted from a set of documents to a frequency-based representation of the source evidence. The frequency-based representation includes multiple signals that each corresponds to an evidence type in the source evidence. The information handing system selects one of the signals that indicates a hidden cycle corresponding to a frequency at which one of the evidence types occurs in the source evidence and extracts hidden evidence from the source evidence based on the hidden cycle to process a request.