Most people don’t get Materials Planning.
To them, it’s just common sense.
It is “just” about buying what production needs, when they need it.
But you and I know that’s far from the truth.
Material Requirements Planning (MRP) is the backbone of production.
It keeps the plant running, orders flowing, and customers happy.
So many aspects can go wrong.
One wrong system setting. One outdated assumption. One missed input.
That’s all it takes for the entire plan to fall apart.
Some time ago, I created a simple but powerful checklist that I shared on LinkedIn to help materials planners and keep operations on track.
Let’s dive in!
1. Ensure Bill of Materials (BOM) is complete with all correct part numbers
Why: If the BOM is wrong, MRP will plan the wrong materials.
Example: A leading personal care brand launched a new shampoo bottle design. The BOM didn’t include the updated pump component. As a result, MRP didn’t plan for it; production ran out mid-batch, causing delays and missed shipments to retailers.
Challenge: BOM updates lag behind engineering changes.
Fix: Link BOM management to MRP and ensure changes are version-controlled.
2. Include proper unit of measure (UoM)
Why: A mismatch in UoMs leads to miscalculations.
Example: Ordering in pallets while MRP plans in units causes massive overstock.
Challenge: Multiple teams use different UoMs.
Fix: Use conversion tables.
3. Validate lead time with supplier
Why: Incorrect lead times mean materials arrive too early or too late.
Example: Planning based on 30 days, but supplier actually takes 45.
Challenge: Lead times in MRP are often based on old quotes, initial contract terms, or assumptions made during onboarding. Over time, actual supplier performance can change.
Fix: Periodically reconfirm lead times with suppliers and update MRP.
4. Calculate supplier lead time variability
Why: Relying only on average lead time ignores risk.
Example: Supplier usually delivers in 20 days, but sometimes in 40.
Challenge: MRP doesn’t factor in variability by default.
Fix: Add safety time or safety stock buffers based on standard deviation.
5. Have the right minimum order quantity (MOQ)
Why: MOQs drive order size and working capital.
Example: MRP generates a 100-unit need, but MOQ is 500.
Challenge: MOQ changes aren’t reflected in system.
Fix: Regularly update MOQs from contracts and vendor feedback.
6. Input the right freight terms
Why: Freight terms directly impact the Estimated Time of Arrival (ETA) and material availability dates in MRP.
Example: Planning assumes DDP (Delivered Duty Paid), expecting goods to arrive at the plant in 14 days. But the actual term is EXW (Ex Works), meaning the buyer is responsible for shipping and the goods won’t arrive for 30 days. Result: missed production schedules.
Challenge: Freight terms are often buried in supplier contracts or not integrated into planning systems, leading to false assumptions.
Fix: Maintain accurate freight terms in supplier master data and integrate them into ETA and MRP logic to reflect the true lead time and delivery responsibility.
7. Keep record of discontinued parts, new parts, and transition dates
Why: MRP will plan materials that are no longer used.
Example: Planning with a phased-out component leads to scrap and rework.
Challenge: Transition plans aren’t always shared with planning.
Fix: Create a system flag and set effective dates for part changes.
8. Confirm open purchase orders (POs) with suppliers
Why: MRP assumes confirmed POs are reliable.
Example: A PO exists, but the supplier never accepted it.
Challenge: Lack of confirmation process.
Fix: Require acknowledgments and update PO status in the system.
9. Keep ready dates and ETAs up to date
Why: ETAs are the heartbeat of MRP rescheduling.
Example: An early shipment isn’t updated; MRP shows a shortage that doesn’t exist.
Challenge: No systematic update of PO ETAs.
Fix: Sync with supplier portals or request regular updates.
10. Keep on-hand inventory data accurate by location, considering quality issues
Why: MRP plans based on what it believes is usable.
Example: System shows 5,000 units, but 2,000 are on hold due to defects.
Challenge: No segregation between usable and non-usable inventory.
Fix: Use inventory status codes and location-specific inventory.
11. Use the most updated MPS (Master Production Schedule)
Why: MRP explodes demand from Master Production Schedule.
Example: Using last week’s MPS leads to misaligned material planning.
Challenge: MPS not refreshed regularly.
Fix: Automate MPS updates and schedule regular reviews.
12. Keep record of changes in the MPS
Why: Without history, it’s not possible understand or explain plan changes.
Example: Why was demand for a part so high last month? No traceability.
Challenge: Overwrites with no audit trail.
Fix: Enable MPS version control or change log tracking in the planning tool.
Conclusion:
MRP isn’t a set-and-forget system.
It’s a living tool that requires clean inputs and constant maintenance.
This checklist helps you avoid the most common challenges that silently undermine material planning and cause panic later.
