Auditing WIP

Many types of businesses — such as homebuilders and manufacturers — turn raw materials into finished products for customers. Production is a continuous process. So, any work that’s been started but isn’t yet completed before the end of the accounting period is reported as work in progress (WIP) under U.S. Generally Accepted Accounting Principles (GAAP).


The value of WIP relies on management’s estimates. Auditors often give special attention to these estimates during fieldwork. Here’s what to expect during a financial statement audit.


Inventory 101


Inventory is classified as a current asset on the balance sheet under GAAP. There are three types of inventory:


  1. Raw materials. These are tangible inputs that have been received from suppliers but haven’t yet been worked with. For example, a construction firm may have a supply of lumber and drywall in a warehouse that counts as raw materials.

  2. Work in progress. This term refers to partially finished products at various stages of completion. Items classified as WIP still require further work, processing, assembly and/or inspection. It includes raw materials, labor and overhead allocations.

  3. Finished goods. These items are fully complete. They may be ready for customers to purchase or, in the case of custom products, available for delivery or title transfer to customers.


Standard vs. job costing


When a company produces large volumes of the same product, management allocates costs as each phase of the production process is completed. This is known as standard costing. For example, if a production process involves eight steps, the company might allocate 50% of its costs to the product once the fourth stage is completed.


On the other hand, when a company produces unique products — such as the construction of a factory or made-to-order parts — a job costing system is typically used to allocate materials, labor and overhead costs as incurred.


Most experienced managers use realistic estimates, but inexperienced or dishonest managers may inflate WIP values. This can make a company appear healthier than it really is by overstating the value of inventory at the end of the period and understating cost of goods sold during the current accounting period.


Eye on WIP