Source documents definition

What are Source Documents?

Source documents are the physical basis upon which business transactions are recorded. Source documents are typically retained for use as evidence when auditors later review a company's financial statements, and need to verify that transactions have, in fact, occurred. They usually contain a description of a business transaction, the date of the transaction, a specific amount of money, and an authorizing signature. Many source documents are also stamped to indicate an approval, or on which to write down the current date or the accounts to be used to record the underlying transaction. 

A source document does not have to be a paper document. It can also be electronic, such as an electronic record of the hours worked by an employee, as entered into a company's timekeeping system through a smartphone.

Importance of Source Documents

Source documents are essential proof that business events have occurred. Otherwise, a business would not be able to prove to its auditors that the transactions from which its financial statements were compiled ever occurred. There may also be times when someone within a business needs to research prior transactions; if so, a well-organized set of source documents, either on paper or digitized, will be needed for this research.

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Examples of Source Documents

Examples of source documents, and their related business transactions that appear in the financial records, are noted below:

  • Bank statement. A bank statement contains a number of adjustments to a company's book balance of cash on hand that the company should reference to bring its records into alignment with those of the bank. Bank statements are sometimes downloaded from the bank on a daily basis, in order to conduct daily bank reconciliations (useful for spotting fraud and understanding the current cash balance).

  • Cash register tape. A cash register tape can be used as evidence of cash sales, which supports the recordation of a sale transaction.

  • Credit card receipt. A credit card receipt can be used as evidence for a disbursement of funds from petty cash. It can also be used as proof when the payables staff is reviewing a credit card statement prior to paying the ending balance noted on it.

  • Lockbox check images. Lockbox check images support the recordation of cash receipts from customers. These images are stored on a bank’s servers, not on the company’s computer systems. This can be an issue, if the bank has a policy of terminating or off-loading these images after a period of time.

  • Packing slip. A packing slip describes the items shipped to a customer, and so supports the recordation of a sale transaction. A copy of it may be used to audit whether deliveries have taken place.

  • Purchase order. A purchase order is a legal authorization issued to a supplier to send the issuer a certain number of units of a particular product, at the price stated on the purchase order. Copies of it are used to confirm arriving goods, as well as to confirm that a supplier invoice has been authorized.

  • Sales order. A sales order, when coupled with a bill of lading and/or packing list, can be used to invoice a customer, which in turn generates a sale transaction. This is an essential document, since it is used to track a customer’s order through a company’s entire process flow until the ordered items have been shipped.

  • Supplier invoice. A supplier invoice is a source document that supports the issuance of a cash, check, or electronic payment to a supplier. A supplier invoice also supports the recordation of an expense, inventory item, or fixed asset in the buying entity’s accounting system.

  • Time card. A time card supports the issuance of a paycheck or electronic payment to an employee. If employee hours are being billed to customers, then it also supports the creation of customer invoices.

For example, a company is in the consulting business. it accumulates hours-worked information from employee timesheets, which is then included in customer invoices that in turn result in the creation of a sale and accounts receivable transaction. Thus, in this situation, the timesheet is the source document for a sale transaction.

Controls Over Source Documents

There are a number of possible controls that can be used to reduce the risk that source documents are not properly recorded in an accounting system. One of the more common controls is to pre-number documents, so that missing documents are easier to track down. Another control is to reconcile the balances in accounts to the supporting source documents to see if either some documents have not been recorded, or if some transactions recorded in the accounts do not appear to have any supporting source documents.

How Long to Retain Source Documents

Various regulations mandate that some source documents be retained for a number of years. It may also be prudent to retain these documents irrespective of regulations, if only to provide evidence in the event of a lawsuit, or to provide better customer service. For these reasons, a company should adopt a document destruction policy that strictly controls the shredding or other form of elimination of source documents until a certain number of years have passed.

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