“Which KPIs would you track?” is one of the most common supply chain interview questions — and one of the most commonly fumbled. Candidates list metric names confidently, then stall when asked to define one. This guide gives you all twenty metrics that come up, with the formula for each and, more importantly, what the number actually tells you.
Part of a series. This is a companion reference to our main supply chain management interview questions guide, which covers the full interview rather than metrics alone.
1. Delivery & Customer Service KPIs
These are the metrics the customer actually feels, and the ones most likely to open a KPI conversation in an interview. Know the difference between them — candidates routinely use on-time delivery and OTIF interchangeably, which is wrong.
On-Time Delivery (OTD)
(Orders delivered on or before the due date ÷ Total orders delivered) × 100
Measures schedule reliability only. An order delivered on time but short-shipped still counts as on time, which is exactly why OTD alone flatters performance.
On-Time In-Full (OTIF)
(Orders delivered on time AND in full ÷ Total orders) × 100
The stricter and more meaningful service measure. Because both conditions must be met, OTIF is always lower than OTD — being able to explain why is a good interview signal.
Order Fill Rate
(Units shipped ÷ Units ordered) × 100
How much of demand you satisfied from available stock. Also measured at line level (line fill rate) and order level (order fill rate) — say which variant you mean.
Perfect Order Rate
(Orders delivered on time, in full, damage-free and with correct documentation ÷ Total orders) × 100
The most demanding service metric, because it multiplies several independent success conditions. It exposes problems that individual metrics hide.
2. Inventory KPIs
Inventory metrics are where supply chain meets the balance sheet, so expect finance-literate follow-up questions. Interviewers frequently ask candidates to calculate inventory turnover on the spot.
Inventory Turnover
Cost of Goods Sold ÷ Average inventory value
How many times inventory is sold and replaced in a period. Higher generally means leaner working capital — but pushed too far it produces stockouts, so it must be read alongside fill rate.
Days Inventory Outstanding (DIO)
(Average inventory ÷ COGS) × 365, or simply 365 ÷ Inventory turnover
The same information expressed as days of stock held. Operational teams usually find days more intuitive than turns, and it feeds directly into the cash-to-cash calculation.
Inventory Record Accuracy
(Count locations matching system record ÷ Total locations counted) × 100
Measured through cycle counting. Everything downstream — MRP, availability promises, replenishment — is only as reliable as this number.
Excess & Obsolete (E&O) Ratio
(Value of excess and obsolete stock ÷ Total inventory value) × 100
Capital tied up in stock that will probably never sell at full value. Rising E&O usually points upstream to forecast bias or over-ordering, not to a warehouse problem.
Stockout Rate
(Order lines unfulfilled due to no stock ÷ Total order lines) × 100
The direct cost of running too lean. Pair it with inventory turnover in your answer to show you understand the trade-off rather than optimising one side blindly.
3. Planning & Forecasting KPIs
If you are interviewing for a planner or analyst role, these will come up. The distinction between accuracy and bias is the single most common thing candidates get wrong.
Forecast Accuracy (via MAPE)
MAPE = Average of ( |Actual − Forecast| ÷ Actual ) × 100; Accuracy = 100 − MAPE
Measures the size of forecast error regardless of direction. Accuracy targets vary enormously by product volatility, so quote it with context rather than as an absolute standard.
Forecast Bias
( Σ(Forecast − Actual) ÷ Σ Actual ) × 100
Measures the direction of error. Persistent positive bias silently builds excess stock; persistent negative bias causes chronic shortages. Errors that cancel out look fine on MAPE but are still a systematic problem.
Schedule Adherence
(Units produced as scheduled ÷ Units scheduled) × 100
How reliably production executes the agreed plan. Poor adherence undermines every downstream promise, and is often caused by upstream material shortages rather than by the factory itself.
4. Procurement & Supplier KPIs
These appear in both procurement and general supply chain interviews. Be ready to say how you would present them to the supplier, not just how you would calculate them.
Supplier On-Time Delivery
(Purchase orders received on or before due date ÷ Total POs received) × 100
The core supplier reliability measure. Define whether early deliveries count as on time — many companies treat early receipt as a failure because it consumes space and cash prematurely.
Supplier Quality / Defect Rate (PPM)
(Defective units ÷ Total units received) × 1,000,000
Parts per million is used because acceptable defect rates in manufacturing are far below one per cent, and percentages lose resolution at that scale.
Cost Savings / Purchase Price Variance
((Baseline price − Negotiated price) ÷ Baseline price) × 100
Always state the baseline and whether it is a hard saving or a cost avoidance. Agreeing the methodology with finance in advance is what makes the number credible.
5. Logistics & Warehouse KPIs
Logistics metrics should be SMART — specific, measurable, achievable, relevant and time-bound — or PACT: purposeful, actionable, continuous and trackable. Quoting one of those frameworks before listing metrics shows structured thinking.
Freight Cost as a Percentage of Sales
(Total freight spend ÷ Net sales) × 100
The headline logistics efficiency measure. It moves with product mix and fuel prices as well as with your own performance, so trend it rather than reading a single month.
Cost per Unit Shipped
Total logistics cost ÷ Total units (or orders, or cases) shipped
Normalises cost against activity, so it separates genuine efficiency change from simple volume change. Choose the denominator that matches how your operation actually scales.
Vehicle / Container Fill Rate
(Actual load used ÷ Maximum capacity) × 100, by weight or by volume
Shipping air is one of the largest avoidable costs in logistics. Measure against whichever constraint binds first — heavy goods cube out slowly, light goods weigh out slowly.
6. Financial & Cross-Functional KPIs
These are the metrics that get supply chain taken seriously by the executive team. Being able to speak in them separates a supervisor from a manager in an interview.
Cash-to-Cash Cycle Time
Days Inventory Outstanding + Days Sales Outstanding − Days Payable Outstanding
How many days cash is tied up between paying suppliers and being paid by customers. Every day removed releases working capital, which is why inventory decisions are treasury decisions.
Total Supply Chain Cost as a Percentage of Revenue
(Plan + source + make + deliver costs ÷ Total revenue) × 100
The broadest efficiency measure, and the one that stops teams optimising one function at another's expense — cutting freight cost by holding more stock is not a saving.
How to Answer a KPI Question in an Interview
Reciting metrics is a weak answer. The structure that lands is: name the metric, define it precisely, say what decision it drives, and acknowledge its limitation. Interviewers are testing judgement, not recall.
Weak answer
“I would track OTIF, inventory turns, fill rate and forecast accuracy.”
Strong answer
“I would start with OTIF, because it captures both timeliness and completeness in one number and is what the customer actually experiences. I would pair it with inventory turnover, because it is always possible to buy a better OTIF by holding more stock — so the two have to be read together. Then forecast accuracy and bias upstream, since most service failures trace back to a planning error rather than an execution one.”
Notice what the strong answer does: it explains the relationship between metrics and shows awareness that any single KPI can be gamed. That is the difference between someone who has read a list and someone who has managed a scorecard.
Five Mistakes Candidates Make with KPIs
Using OTD and OTIF interchangeably
They measure different things and OTIF is always lower. Mixing them up signals inexperience immediately.
Quoting benchmarks without context
There is no universal good inventory turn figure — it varies by industry, product shelf life and business model. Say what it depends on.
Ignoring the trade-offs
Every service metric can be improved by spending more on stock or freight. A metric quoted without its counterweight looks naive.
Listing too many metrics
A scorecard everyone ignores is worse than four metrics that drive weekly decisions. Prioritise, and explain the prioritisation.
Forgetting the financial metrics
Cash-to-cash cycle time and total supply chain cost are what the executive team cares about. Candidates who mention them stand out.
Not knowing the formula
If you name a metric, assume you will be asked to define it. Never name one you cannot calculate on a whiteboard.
Next steps. Inventory turnover and DIO make far more sense once you understand the underlying stock policies — see inventory management techniques explained. For role-specific preparation, work through our logistics executive and procurement question sets.
Frequently Asked Questions
What is the difference between OTD and OTIF?
On-Time Delivery measures only whether an order arrived by the due date. OTIF requires the order to be both on time and complete, so a partial shipment delivered on schedule passes OTD but fails OTIF. OTIF is always the lower and more meaningful of the two figures.
How do you calculate inventory turnover?
Inventory turnover equals cost of goods sold divided by average inventory value for the same period. It shows how many times stock is sold and replaced. Dividing 365 by the turnover figure converts it into days inventory outstanding.
What is the difference between forecast accuracy and forecast bias?
Forecast accuracy, usually measured through MAPE, captures the magnitude of error regardless of direction. Forecast bias captures the direction — whether you consistently over- or under-forecast. A forecast can have acceptable accuracy while carrying a damaging systematic bias.
What is the perfect order rate?
The percentage of orders delivered on time, in full, undamaged and with correct documentation. Because all conditions must be satisfied simultaneously, it is the most demanding service metric and exposes failures that single-condition metrics hide.
What is cash-to-cash cycle time?
Days inventory outstanding plus days sales outstanding minus days payable outstanding. It measures how long cash is tied up between paying suppliers and collecting from customers, and is the metric that connects supply chain decisions to the finance team's priorities.
What is a good number of KPIs to track?
Few enough that each one drives a decision. A focused scorecard of eight to twelve metrics aligned to strategy outperforms a dashboard of fifty that nobody acts on. In an interview, say which metrics you would choose and why, rather than listing everything you know.
Learn to Manage the Numbers, Not Just Quote Them
Understanding how these metrics interact — and which lever to pull when one moves the wrong way — is what employers pay for. Edusphere's logistics and supply chain diplomas cover inventory control, performance measurement and cost management in a Singapore business context.
