text: FM 2-22.3
  Appendix B
  Source and Information Reliability Matrix
  SOURCE RELIABILITY
  B-1. Reliability ratings range from “Reliable” (A) to “Unreliable” (E) as shown
  in Table B-1. In every instance the rating is based on previous reporting
  from that source. If there has been no previous reporting, the source must be
  rated as “F”. [NOTE: An “F” rating does not necessarily mean that the
  source cannot be trusted, but that there is no reporting history and therefore
  no basis for making a determination.]
  Table B-1. Evaluation of Source Reliability.
  A Reliable No doubt of authenticity, trustworthiness, or
  competency; has a history of complete reliability
  B Usually Reliable Minor doubt about authenticity, trustworthiness,
  or competency; has a history of valid information
  most of the time
  C Fairly Reliable Doubt of authenticity, trustworthiness, or
  competency but has provided valid information in
  the past
  D Not Usually Significant doubt about authenticity,
  Reliable trustworthiness, or competency but has provided
  valid information in the past
  E Unreliable Lacking in authenticity, trustworthiness, and
  competency; history of invalid information
  F Cannot Be No basis exists for evaluating the reliability of the
  Judged source
  INFORMATION CONTENT
  B-2. The highest degree of confidence in reported information is given to that
  which has been confirmed by outside sources, “1”. Table B-2 shows evalua-
  tion of information content. The degree of confidence decreases if the
  information is not confirmed, and/or does not seem to make sense. The
  lowest evaluated rating of “5” means that the information is considered to be
  false. [NOTE: A rating of “6” does not necessarily mean false information,
  but is generally used to indicate that no determination can be made since the
  information is completely new.]