Somewhere out there, one of your customers has just ordered a blue t-shirt. In a medium. It’s nothing particularly exotic. There’s nothing that’s specifically odd about the order. It’s just one order line of one unit. Quite honestly, it’s the kind of order that your operation handles thousands of times a week, and most of the time, it can do it without anyone breaking into a sweat.

However, somewhere between the purchase and the customer’s doorstep, that order is going to pass through at least half a dozen places where something could go very wrong with it. And that’s because every logistics operation, however good it is, is really only ever a sequence of opportunities for one specific mistake to happen in one (or maybe more?) specific place(s).

Which brings me to what we’re going to talk about.

Because every warehouse error usually has two parts to it. The first one is where the original ‘crime’ happened, and then the second one is where it was discovered. They are almost never the same place, and often, extremely excitingly, they are also a long time apart, timewise.

Which is what can make your job feel rather less like operations management and rather more like a long-running episode of Cluedo.

Because it wasn’t the picker in the aisle with the scanner. It was goods-in, three weeks ago, with a clipboard.

So, let’s follow that blue medium t-shirt through the building and have a look at the usual suspects…

Goods-in: believing your paperwork

The signature crime at goods-in is incredibly simple: all you have to do is believe your paperwork. The ASN says it’s 100 units, but the pallet only has 96 on it. But the person with fourteen more lorries queuing outside checks in 100 units, because while the paperwork looked absolutely fine, the queue outside looked rather cross.

Crime committed. But crucially, nobody’s realised it’s happened. Your system now believes fully in four units that do not exist, and it will go on believing in them with total sincerity until you tell it differently. The discovery of this ‘crime’ will only come weeks later, at the far end of the building, when one of your pickers arrives to collect the last four blue mediums and finds fresh air instead.

The crime happened at the dock door, but the ‘body’ turned up in aisle 14, and well after the fact.

This is why Dispatcher WMS can be configured to make goods-in scan what arrived rather than just rubber-stamp what was promised. And that’s because if you count incoming goods at the door, you’ll capture any shortfall at the door, and those phantom units won’t even make it into your warehouse. Which is important, because if you catch them at the scene of the crime, they’ll cost you an email to the supplier instead of a failed order and an apology to a customer. (And it also means that your supplier’s ASN record will take the blame that it deserves, which, over time, is how your wider supply chain will tidy itself up too.)

Putaway: when stock gets a new identity

Putaway’s ‘criminal’ speciality is when you accidentally give your stock a new identity. Yes, we know that the pallet exists. Yes, we know that it’s in the building (somewhere). It’s just… not where the system thinks it is. And that’s because when they were looking for somewhere to put it away, someone put it in 14-C because 14-B was blocked. And they were fully intending to mention it to somebody, but then lunch happened.

So, your stock hasn’t been stolen. But it has been relocated (sort of like a mob informant). It will now live, completely undisturbed, under its new identity, for months.

And all the while, the location the system believes that it’s in will get picked against, counted against, and eventually stared at in frustrated disbelief during a stock take.

The fix here is system-directed putaway, with scan-to-confirm. Dispatcher WMS tells you where it wants you to put the pallet, your operator scans the location where they actually put it, and any disagreement between those two locations is uncovered in the moment. It sounds kind of modest on paper: your system’s map of the warehouse should match the actual warehouse. Pretty obvious, when you think about it. But it only sounds trivial if you’ve never worked somewhere that this just doesn’t happen. Blue Yonder’s own numbers for Dispatcher WMS users put inventory accuracy at near-100% for well-run sites, and this, right here, is most of how you can achieve it for yourself.

Picking: the lookalike problem

Picking’s signature error is the lookalike.

Blue medium, blue large. Meh. Close enough.

You’ve got two product codes that are separated by a single character. Two SKUs that are, to all intents and purposes, and especially during hour seven of a shift, entirely the same thing. Your picker isn’t the villain here. They’re being asked to identify something minuscule, however many times an hour. And in this case, the ‘suspects lining up against the wall’ all turned up wearing the same thing, they all have a wild handlebar moustache and the only way you could tell them apart if you TRIED would be one stinkin’ letter that’s hidden somewhere on the label of the t-shirt they’re wearing.

If you’re lucky, Packing will catch it.

If you’re less lucky, the customer will catch it and will give you a one-star review. Either way that mispick will probably go on to commit a second, sneakier crime: because the location it came from is now wrong by one unit, and the location it should have come from is wrong by one unit the other way. And those discrepancies are tiny little time bombs, ticking away silently, already located under two future orders.

The fix for this is barcode validation at the point of pick. Scan the item, and the wrong blue t-shirt simply refuses to be picked. Which means that you have to find the right one. Which will uncover the problems that have created the issue in the first place, which subsequently means that they can get fixed.

If you’re able to do this, that error will get fixed at almost no cost to anyone. And that’s because Dispatcher WMS regulates what actually gets picked, and if you’re sent to a location where your stock is not found, the system can also be configured to automatically drop into a stock check to correct any errors on the fly.

Packing and dispatch: the classic swap

By now our blue medium t-shirt has survived three of the classic hazards, and it’s reached packing. Which is the home of the classic swap: you’ve got two orders on your bench, and two labels have been printed out. But during one moment of distraction, orders that had been picked perfectly, and packed beautifully, are now travelling (at speed) towards each other’s customer.

A bigger version of this can also happen during shipping: a pallet is confidently loaded onto the wrong trailer and eventually it’ll find itself in a depot two hundred miles from the person who wanted it.

Scan-to-pack and dispatch verification shut both of these issues down. The label has to match the order, the carton has to match the consignment, the pallet has to match the trailer, IF they want to get out of the dock door.

And anything that disagrees with any of those things, at any point, will simply be stopped, rather than needing to be explained afterwards.

Out of your jurisdiction: errors past the dock door

Rest assured, mistakes like these can be the gifts that just keep on giving, even after they’ve left your dock doors. And that’s because the supply chain doesn’t stop stuffing things up just because you have. Perhaps your carrier mis-sorted something. Perhaps the POD vanished. Maybe your customer’s neighbour signed for their package and then promptly went on holiday for a couple of weeks. You can’t control what’s outside your control.

But you can know, precisely and provably, what left your building, when, and in what condition. Which makes every “your warehouse got it wrong” conversation into a much shorter, and considerably more enjoyable one.

Returns: the final destination

And then there’s returns; the Final Destination. It’s where every error that wasn’t caught will eventually come home to roost.

If you wanted to perform a free audit of your operational errors, you could simply spend a week in your returns bay (take a notebook). Because it’s all there.

Exposition time: everyone in the library

Cluedo-ly-speaking, it’s time to gather everyone together in the Library…

Every one of the ‘crimes’ we’ve talked about was committed in one place and then discovered in another. And in our experience the further any error travels from the ‘scene of the crime’ before it’s found, the more it costs to fix.

Luckily, the fix you need isn’t six different fixes. It’s one fix that’s done six times.

And that’s to make sure that the checks you need to do take place when the actions you need to check are in the process of happening. And when you strip everything else out, that’s most of what a WMS like Dispatcher actually does. Yes, it’s much cleverer than that, but at its root, increasing your inventory accuracy is simply a building-sized insistence that reality and your system have to agree, right now, in real time, all of the time, transaction by transaction.

If your warehouse currently feels more like an unsolved mystery than you’d like it to, we’d love to take a look at it. Book an obligation-free discovery call and bring your best whodunnit with you. You’re not going to shock us, because we can assure you, we’ll have seen far worse.

Reducing warehouse errors: FAQ

Where do most warehouse errors actually happen?

Most of them start at goods-in, putaway, picking, or packing and dispatch. Goods-in errors come from trusting a supplier ASN instead of counting what turned up. Putaway errors come from stock ending up somewhere other than where the system thinks it is. Picking errors come from SKUs that look identical at hour seven of a shift. Packing and dispatch errors come from the right stock combining with the wrong label, carton, or trailer.

Why are inventory errors discovered so long after they’re made?

Because where the error happens and where it gets found are almost never the same place. A shortfall that was accidentally waved through at the dock door usually only surfaces weeks later, when a picker arrives to collect stock that was never there in the first place. Your system believes in those units until something forces it to compare its records against reality. The further the error travels before it is caught, the more it costs to put right.

How does a warehouse management system reduce picking errors?

Through barcode validation at the point of pick. Your picker scans the item, and the wrong SKU simply refuses to be picked. Dispatcher WMS can also be configured so that a pick against a location with no stock in it drops straight into a stock check, so the discrepancy gets corrected there and then – instead of at the next count.

What is system-directed putaway?

It is where your WMS tells the operator which location to use, and the operator scans the location they actually used to confirm it. If those two disagree, you’ll find out right away. The result is that your system’s map of the warehouse matches the actual warehouse.

Can a WMS prevent errors at goods-in?

Yes. Dispatcher WMS can be set up so goods-in scans what arrived rather than rubber-stamping what was promised. Any shortfall is captured at the door, before those phantom units make it into your inventory.

What inventory accuracy can a warehouse realistically achieve?

Blue Yonder’s own figures for Dispatcher WMS put inventory accuracy at near-100% for well-run sites. Getting there depends less on one clever feature and more on verification happening consistently at every transaction point, from receiving through to dispatch.