Inventory causes too many headaches in supply chain. No one escapes it.
In my view, we will always experience some level of pain. That’s the reality. But, if we can ease the pain or reduce it to mild discomfort, I’ll take it.
To get on this path, it is critical to set the inventory parameters correctly. As planners, we can’t afford to have them wrong.
I posted an infographic on LinkedIn with the 12 key parameters, covering concepts and formulas.
In this article, I go a level deeper to explain why we set these parameters, the common challenges we face, and how to address them.
Let’s dive in!
1. Safety Stock
Why We Set It
To avoid stockouts. There can be unexpected demand spikes or supplier delays. The safety stock protects customer service and ensures continuity.
Challenges and How to Address Them
Unreliable data – Clean historical data and exclude anomalies
Variable lead times – Track actual performance and update regularly
One-size-fits-all settings – Use segmentation (e.g., ABC) for tailored safety stock levels
Static values – Review monthly or after major demand or supply shifts
2. Cycle Stock
Why We Set It
To ensure there is enough inventory to meet regular demand between planned replenishments. We are talking about regular or common demand here. Cycle stock supports smooth operations without interruptions.
Challenges and How to Address Them
Outdated order quantities – Adjust regularly based on current demand trends
Irregular consumption – Use average usage over time, but watch for seasonality
Mismatch with lead time – Align cycle stock with actual replenishment frequency
Static settings – Review quarterly or when there are changes in demand, packaging, or replenishment strategy
3. Service Level
Why We Set It
To make sure the company has enough product available when customers want to buy. A high service level means fewer stockouts and better customer satisfaction.
Challenges and How to Address Them
- Unrealistic service targets – Use ABC classification to assign more reasonable goals based on product importance
- Mismatch with supply capabilities – Align service levels with actual supply chain performance and lead time reliability
- Hidden stockouts – Track lost sales or backorders to avoid underestimating performance gaps
- Static targets – Review monthly or during S&OP reviews, especially after shifts in customer behavior or supply conditions
4. Backorder Level
Why We Set It
To monitor how often the company fails to fulfill orders on time. Tracking backorders helps identify gaps in planning, inventory, or supply performance.
Challenges and How to Address Them
- Inconsistent definitions – Align teams on what counts as a backorder (e.g., partial vs. full delays)
- Lack of visibility – Integrate data from order systems, warehouse, and customer service to capture full picture
- No root cause tracking – Categorize backorders by reason (e.g., supply delay, forecast error) to fix recurring issues
- Neglected monitoring – Review weekly for key SKUs or high-priority customers to stay ahead of service problems
5. Economic Order Quantity (EOQ)
Why We Set It
To find the most cost-effective order size that balances ordering costs (like purchase processing or setup time) with holding costs (like storage or obsolescence). EOQ helps minimize total inventory cost while ensuring availability.
Challenges and How to Address Them
- Outdated cost assumptions – Regularly update holding and ordering cost data, especially when inflation or logistics costs change
- Not accounting for real constraints – Adjust EOQ for minimum order quantities, transportation limits, or supplier requirements
- Infrequent recalculation – Revisit EOQ at least once a year, or when there are major changes in volume, cost, or supply chain setup
- One-size-fits-all application – Segment products based on demand and cost sensitivity; not every SKU benefits equally from EOQ
6. Lot Size
Why We Set It
To define the quantity to be ordered or produced in one batch, based on efficiency, cost, and operational constraints. A well-set lot size helps reduce setup time, improve production flow, and align with supplier or machine capabilities.
Challenges and How to Address Them
- Fixed lot sizes not aligned with demand – Adjust lot sizes based on demand trends to avoid excess inventory or frequent changeovers
- Ignoring storage or transport capacity – Consider warehouse space, truckload sizes, or production limits when defining lots
- Supplier-imposed constraints – Work with suppliers to renegotiate minimum order quantities or explore consolidation strategies
- Using the same lot size across product types – Tailor lot sizes for high vs. low runners, perishables vs. non-perishables, and stable vs. variable demand
7. Min-Max
Why We Set It
To automate replenishment by setting clear inventory thresholds: the Min triggers reordering when stock drops below it, and the Max defines the upper limit to avoid overstocking. It simplifies planning and ensures consistent product availability.
Challenges and How to Address Them
- Static settings – Update Min and Max values regularly to reflect changes in demand, lead time, and supply reliability
- Set too close together or too far apart – Review frequency of ordering and holding capacity to avoid constant reorders or bloated stock
- Not tailored by product type – Segment SKUs (e.g., fast vs. slow movers) and apply different Min-Max strategies
- Lack of visibility into actual consumption – Use historical usage and forecast data to adjust thresholds more accurately
8. Lead Time
Why We Set It
To define how long it takes from placing an order to receiving the goods. Accurate lead time helps planners schedule replenishment, avoid stockouts, and maintain service levels.
Challenges and How to Address Them
- Using theoretical instead of actual lead time – Measure real performance using historical data, not just what’s promised by suppliers
- Ignoring variability – Track not only average lead time but also delays and fluctuations to improve safety stock accuracy
- Lead time not updated in systems – Set a process to review and refresh lead time regularly in planning tools and ERP
- Assuming lead time is the same for all locations or SKUs – Adjust based on geography, supplier, product type, or shipping method
9. Days of Supply
Why We Set It
To understand how long current inventory will last based on forecasted or average demand. It helps planners assess inventory health, spot overstock or risk of stockout, and align replenishment timing.
Challenges and How to Address Them
- Using outdated or incorrect demand data – Base calculations on the most recent and reliable forecasts or rolling average consumption
- Not segmenting by SKU or location – Different products and regions may have very different consumption patterns
- Assuming stable demand – Monitor for seasonality, promotions, or external events that may affect consumption rates
- Lack of alerts for low or high coverage – Set thresholds in dashboards or systems to trigger reviews before issues escalate
10. Inventory Turnover
Why We Set It
To measure how often inventory is sold and replaced within a given period. It helps assess how efficiently inventory is managed and highlights potential overstock or slow-moving items.
Challenges and How to Address Them
- Incomplete or inaccurate cost data – Use cost of goods sold (COGS) or net sales consistently across periods
- Lumping all products together – Break down turnover by product category or location to get actionable insights
- Not accounting for seasonality – Compare turnover across equivalent periods (e.g., year-over-year) to avoid misleading trends
- Interpreting high turnover without context – Check service levels and stockouts—high turnover isn’t always positive if availability is suffering
11. Reorder Point
Why We Set It
To trigger replenishment before inventory runs out. It ensures new stock arrives in time, based on expected demand during lead time, helping to maintain service levels without rushing orders.
Challenges and How to Address Them
- Set without factoring variability – Combine average demand with safety stock to protect against demand or lead time fluctuations
- Not updated when demand or lead time changes – Review regularly to reflect shifts in customer behavior or supplier performance
- Applying a single rule across all SKUs – Tailor reorder points by product type, seasonality, or criticality
- Disconnect between planning and system settings – Ensure the ERP or inventory system reflects current, agreed-upon reorder points
12. ABC Classification
Why We Set It
To prioritize inventory management efforts based on item importance. It helps focus planning, stocking, and service levels on high-impact SKUs (A-items) while simplifying control over less critical ones (B and C-items).
Challenges and How to Address Them
- Using only sales volume – Consider other dimensions like margin, frequency of use, or strategic importance
- Not updating classifications – Reclassify at least semi-annually to reflect changes in demand, product life cycle, or customer value
- Treating all items the same – Apply differentiated service levels, safety stock, and review frequency based on category
- Manual or inconsistent methods – Automate classification using data-driven rules to ensure consistency and transparency
Conclusion: These 12 inventory parameters are essential. Equally important is to keep them updated. ‘Set and forget’ doesn’t work well with inventory management.
