 Ibn al-Madīnī specialized in the disciplines of hadith, biographical evaluation and "al-ʻIlal", hidden defects, in the "sanad", chain of narration.He was praised by other hadith specialists for his prowess in that field—by both his contemporaries, students and his teachers.ʻAbd al-Raḥmān ibn Mahdī, a scholar who preceded him, described Ibn al-Madīnī the most knowledgeable person of prophetic hadith.