Examples of techniques for analyzing well data which may be encountered during formation testing are disclosed. Certain portions of the tests may exhibit an indication of anomalous behavior, defects, errors or events that may have occurred during testing. One or more confidence tokens may be identified during or after the execution of a test. One or more of these confidence tokens may be analyzed to determine whether such anomalous behavior, defects, errors or events have occurred during the test. These confidence tokens may then be used to determine a level of confidence in the results derived from the tests performed and/or their underlying data and interpretation.