Criticism may arise on any of the following grounds:
These are ten: five pertain to ʿadāla (uprightness), and five to ḍabṭ.1 They are not separated into two groups, so that they can be arranged in descending order of severity.2
The science of jarḥ and taʿdīl, the two grounds of evaluation, when criticism overrides praise, and who needs tazkiya.
The Ḥanafīs classify narrators into four (or, on some accounts, five) groups, including the al-mastūr and majhūl categories with their five-case treatment.
A muʿallal ḥadīth contains a hidden defect (ʿilla) damaging to its soundness, detected by warning signs in sanad and matn that arise to one familiar with the art.
When a narrator's solitary transmission is suspected, others' parallel narrations are mutābaʿa or shāhid; the pursuit of these is al-iʿtibār.
