1. A method of managing data in a nonvolatile memory array comprising: reading stored data from the nonvolatile memory array; deriving raw probability information from the stored data; providing the raw probability information to a decoder, the decoder calculating output probability information from the raw probability information and from an encoded pattern in the stored data; calculating quality information for the stored data, the quality information reflecting the amount of correction performed by the decoder; and changing at least one operating parameter of the nonvolatile memory array in response to the quality information.