9126-1 Quality Model: Maintainability
5. A set of attributes related to the effort needed to make specified modifications. Modifications may include corrections, improvements or adaptation of software to changes in environment, and in requirements and functional specifications.
5.a Analyzability, attributes related to the effort needed for diagnosis of deficiencies or causes of failures, or for identification of parts to be modified.
5.b Changeability, attributes related to the effort needed for modification, fault removal or for environmental change.