A jurist may call an act wajib while another calls it fard, partly because legal schools do not all preserve the same technical distinction between the two terms. The label alone cannot determine the substantive disagreement.
Three matters must be examined:
1. What legal evidence establishes the ruling?
2. Is its transmission and indication definitive, or is relevant uncertainty possible?
3. How does the jurist's school use the technical labels fard and wajib?
This method helps distinguish a genuine dispute over evidence from a difference in terminology.