Cost item 1 – Parts and service hours
The first and most obvious cost of a DOA is the defective part itself. In many cases, attempts are made to repair the part, but the research shows that this is often more expensive than simply writing it off. In fact, many parts prove unsuccessful to repair, so the repair effort is mostly additional time and expense.
On top of that are the hours of Field Service Engineers (FSEs). Every DOA means that an engineer cannot complete his work and a new appointment is required. This not only costs travel time and labor costs, but also causes the end customer to experience longer downtime. The study shows that the use of FSEs averages about $300 per DOA. When these costs are added to the depreciation of the part itself, the damage cost quickly rises to more than the original value of the part. In the cases studied, the combined cost of scrap and service came to between 102 and 142 percent of the part value.
As a result, even before there is additional transportation or inventory pressure, a single DOA turns the balance sheet negative. Damage and service hours alone make it clear that a DOA is much more than a logistics incident and leads directly to margin loss.
Cost item 2 – Transportation
In addition to damage and service hours, transportation costs are a second major expense. Whereas a regular shipment costs about 150 euros on average, an expedited shipment can amount to about 1,200 euros. The study shows that for DOAs, express delivery is chosen much more often: in about 14 percent of cases, compared to only 4 percent for regular deliveries.
On top of that, defective parts usually have to be returned for repair or triage. This again generates additional transportation costs. All in all, this adds up to an average additional cost of about 491 euros per DOA, purely on transportation. Depending on the value of the part, this means an additional charge of 3 to 69 percent on top of the original part value.
Transportation costs thus appear to be a silent accelerator of overall DOA losses. Especially since the pressure to help customers quickly is great, emergency transports are often used automatically, even though they greatly increase the cost per DOA.
Cost item 3 – Inventory and availability
The third cost of a DOA is less visible, but at least as drastic in the long run: the impact on inventory management and availability. When parts regularly arrive defective, higher safety stock levels become necessary to guarantee service levels. That means additional capital investment, increased storage costs and a higher likelihood of obsolescence or depreciation of inventory.
The study shows that DOAs increase inventory costs by an average of 2.35 to nearly 10 percent per year, depending on demand frequency and part delivery times. Converted to the value per DOA, this amounts to an additional cost of 8 to 47 percent of the part value. This makes inventory a structural factor in the total cost of a DOA.
The problem is that these costs are rarely directly visible in reports. Yet they put noticeable pressure on margins, as inventory policies often have to be forced to change in order to meet SLAs. This creates a vicious cycle: higher DOA ratios lead to more inventory, more inventory leads to higher costs and a higher chance of waste.
The sum: why one DOA costs more than 100 percent
When the three cost items are added together, it becomes clear how big the impact really is. Damage and service hours already yield, on average, 102 to 142 percent of the part value. Transportation costs add 3 to 69 percent and inventory costs another 8 to 47 percent. The study shows that the total cost of a single DOA thus amounts to 135 to 219 percent of the original part value.
On an annual basis, this translates to a loss of nearly 4 percent of spare parts sales at the organizations surveyed. For companies with margins of 20 percent or less, this means that one out of every five euros of profit evaporates due to DOAs. This makes DOAs not incidents to be taken for granted, but structural margin killers that affect the entire chain.