A method of and system for discovering and reporting the trustworthiness and credibility of calling party number information, such as Automatic Number Identification (ANI) or Calling Number Identification (Caller ID) information, or for inbound telephone calls. The disclosed method entails the use of real time telephone network status and signaling, network data, locally stored data, and predictive analytics. Practice of the disclosed method is neither detectable by nor intrusive to the calling party, and the method can be implemented into existing enterprise, telecommunications, and information service infrastructures.