Indicators are measures with associated decision criteria. Decision criteria are defined with threshold  values, which are alarms of poor-quality levels. We have defined thresholds by using ROC curves, the Bender  method and ATEMA for a group of structural measures and understandability, modifiability and correctness. Correctness: the degree to which a model does not have workflow errors or faults, such as deadlocks.  Understandability: attributes of models that have a bearing on the users' effort to recognize the logical  concept and its applicability.  Modifiability: degree to which a model can be effectively and efficiently modified without introducing  defects or degrading existing product quality   Authored: Laura Sánchez-González, Félix García, Francisco Ruiz; Last updated: February 2015 More Information: University of Castilla-La Mancha Alarcos Research Group: +34 926 295300 ext.96678 Ciudad Real - Spain                      Laura Sánchez-González, Félix García, Francisco Ruiz