Different categories of hadith (sayings attributed to the Prophet Muhammad) have been used by various scholars.
Experts in hadith studies generally use two terms - taqrīr for tacit approvals, and khabar for sayings and acts ascribed to Muhammad.
The term taqrīr implies that, in the presence of Muhammad a believer did something, which the Prophet noticed but did not disapprove or condemn.
It is on the basis of this premise that the Muslim scholars hold that a hadith offers a ẓannī (inconclusive/probably true) evidence.
In one of the major works in the science of hadith, Al-Khatib al-Baghdadi has divided the individual narratives in the following categories, according to their epistemic value:[6]