Deletions: missing relations in places a relation ought to be identified. An example of deletion in this task is delete the has_diagnosis 'لٌ ٠ ر قْ ١ٔ ' relation between the Cases_of_disease ' ؽب خٌ ا وٌّٗ ' and Diagnosis_of_disease ' ر قْ ١ ا وٌّٗ ', when we delete this relation the system could not identify the diagnosis of disease.
Insertions: postulating any relation to hold where none ought to been. An example of insertion in this task is insert new (Especial_Disease 'وِ بٔكه ') relation between the symptoms and disease, when we insert this relation the diagnosis of disease will not be accurate.
Substitutions: postulating a specific relation to hold where some other ought to been. For example if we substitute any relation with other relation, diagnosis of disease will not be accurate.