The following factors influence the reliability of audit evidence:

1. Source of Evidence:
   Audit evidence obtained from independent external sources is generally more reliable than evidence obtained from internal sources.
2. Effectiveness of Related Controls:
   Evidence generated internally is more reliable when the internal controls over its preparation and maintenance are strong and effective.
3. Directness of Evidence:
   Evidence obtained directly by the auditor, such as through observation or physical examination, is more reliable than evidence obtained indirectly, such as through inquiry.
4. Documentary Form of Evidence:
   Evidence that exists in written or documented form (e.g., contracts, invoices) is more reliable than verbal evidence. Original documents are more reliable than copies or electronic versions.