Vouching is a technical term that refers to the inspection of documentary evidence supporting and substantiating a financial transaction, by an auditor.
Vouching is defined as the "verification of entries in the books of account by examination of documentary evidence or vouchers, such as invoices, debit and credit notes, statements, receipts, etc.
By using a vouching or a voucher system a company will have concrete and solid documentation and evidence of expenses, capital, and written proof in audits.
This means that the auditor must conduct vouching with great importance, if not, he can be charged with negligence which happened in the case of Armitage v. Brewer and Knott.
When delivering the decision the Judge stated that "It was clear that a good many documents were suspicious on either face and called for Inquiry".