Hadith report, the scale of the report's transmission, the routes through which the report was transmitted, and the individual narrators involved in its transmission. On the basis of these criteria, various classifications were devised for hadith. The earliest comprehensive work in hadith studies was Abu Muhammad al-Ramahurmuzi's "al-Muhaddith al-Fasil", while another significant work was al-Hakim al-Naysaburi's "Ma‘rifat ‘ulum al-hadith". Ibn al-Salah's "ʻUlum al-hadith" is considered the standard classical reference on hadith studies. By means of hadith terminology, hadith are categorized as "ṣaḥīḥ" (sound, authentic), "ḍaʿīf" (weak), or "mawḍūʿ" (fabricated). Other classifications used also include: "ḥasan" (good), which refers to an otherwise
Criticism of Hadith According to Racha El Omari, early Mutazilites believed that hadith were susceptible to "abuse as a polemical ideological tool"; that the "matn" (content) of the hadith -- not just the "isnad" -- ought to be scrutinized for doctrine and clarity; that hadith "supported by some form of "tawātur"", i.e. by a large number of "isnād" strands, each beginning with a different Companion, were valid. In writing about "mutawatir" (transmitted via numerous chains of narrators) and "ahad" (any ahadith that is not "mutawatir") and its importance from the legal theoretician's point of view, Wael Hallaq notes the medieval scholar Al-Nawawi argued