What is the JIT versus safety stock decision?
Just in time (JIT) and safety stock are two opposing principles for inventory management. JIT minimizes inventory by delivering as close as possible to actual demand, with minimal buffers and short lead times. Safety stock deliberately builds buffers to absorb unexpected demand peaks, supplier failures or transport disruptions. Both are legitimate strategies, but they deliver very different outcomes on cost, service level and risk.
For most shippers the right outcome is not an extreme but a deliberate hybrid in which the right choice is made per SKU segment. Fast-moving, predictable products with reliable suppliers deserve a JIT approach. Critical SKUs without alternative, or products with strongly variable demand, deserve appropriate safety stock. A one-size-fits-all approach structurally leaves value or risk control on the table.
The pandemic has painfully shown that an extreme JIT setup without buffers is also extremely vulnerable. Many shippers have since revised their inventory strategy, not to abandon JIT entirely but to place buffers more targeted where the impact of a disruption would be greatest.
When is a recalibration relevant?
A recalibration of your inventory strategy is sensible at multiple moments. With inventory cost reviews showing current levels no longer align with demand or risk. After supply chain disruptions that have exposed where your chain is vulnerable. With portfolio expansion where new product categories require different inventory profiles. With changing customer requirements (express deliveries, shorter lead times) that render the current strategy outdated. And proactively, with board questions about supply chain resilience.
Specifically for shippers who have historically inherited their inventory strategy from an original parent company or best practice from another sector, a structured recalibration is often valuable. What works well in the auto industry rarely works well in food retail, and vice versa.
Our approach
We segment your SKU portfolio based on turnover speed, margin, demand variability and strategic importance. This yields a fitting inventory strategy per segment, instead of one rule for everything.
Per segment we map current inventory levels, inventory costs, service levels and stockout frequency. This provides a factual basis for the current situation and the pain points that need attention.
Per SKU segment we model three to five scenarios with different inventory strategies. Per scenario we calculate TCO (inventory cost, stockout cost, transport cost, quality cost) over a three-year horizon.
We weigh the scenarios against each other, also against non-financial criteria such as supply reliability and flexibility. Per segment we formulate a recommended strategy with substantiation.
We deliver a phased implementation roadmap with timeline, dependencies and milestones. Implementation is handed over to your internal team or we support it as a project.
What you get
- SKU segmentation matrix with strategic classification per product
- Current state analysis with cost, service level and stockout overview
- TCO scenario comparison per segment, open and repeatable model
- Recommended inventory strategy per SKU segment with substantiation
- Implementation roadmap with phasing, dependencies and milestones
- Board-ready presentation for decision-making
Frequently asked questions
When does JIT fit and when safety stock?
JIT fits well with predictable demand, short and reliable lead times, local suppliers and low variability in volume. Safety stock fits better with unpredictable demand, long lead times, critical SKUs without alternative, and high disruption risk. For most shippers the outcome is not an extreme: a hybrid where the right model is applied per SKU segment.
How has COVID changed thinking about JIT?
Before COVID JIT was the standard in many sectors, driven by cost optimization and best practices from the auto industry. The disruption of 2020 and 2021 painfully showed that extreme lean inventory is also extremely vulnerable. The current consensus is that JIT still makes sense for predictable components, but that critical SKUs deserve a deliberate buffer. The pendulum swings from efficiency to resilience.
How do you calculate the right safety stock?
Safety stock calculation combines demand variability, lead time variability, target service level and stockout costs. Common formulas work with statistical distribution (z-score for service level) and historical data. We model this per SKU segment based on your own data, not via standard rules. The right answer differs strongly per product and per market.
What is the service level impact of a choice between JIT and safety stock?
Service level is a direct outcome of your inventory choice. Strict JIT typically yields lower service level under unpredictability, but lower inventory costs. Safety stock at the right level yields high service level against higher inventory costs. A good strategy explicitly determines which service level you want to offer per customer category and builds the inventory model around it, not the other way around.
Do you work with specific inventory management software?
Our analyses work mostly in a combination of Excel modeling and specific inventory optimization software, depending on the scale and complexity of your portfolio. At implementation we advise which tools best fit your situation, from integrated ERP modules to dedicated planning software. We always deliver the underlying models so you can repeat internally.
A recalibration of your inventory strategy?
Schedule a call where we walk through which SKU segments fit in scope and what a recalibration would deliver.