White Belt · 13 min

The eight wastes: what you are actually looking at

After this you can

name the eight wastes and give an example of each from a process I know.

A warehouse manager was asked why picking took so long. He said his pickers were slow and asked for two more. Someone followed one picker for a single order and wrote down every minute. Thirty-three minutes, of which two were spent picking anything. The pickers were not slow. They were walking, searching, queuing and re-scanning — and every one of those minutes was invisible, because nobody had a name for them.

The idea

Waste is anything the customer would not pay for. That definition is easy to nod at and hard to apply, because from inside a process almost everything feels necessary. So Lean gives you eight named categories. They are not a taxonomy to memorise — they are a set of prompts that make invisible time visible.

The classic seven come from Taiichi Ohno at Toyota. The eighth was added later and is about people rather than material.

Transport — moving things that did not need to move. Parts across a factory, files between departments, a document emailed to four people in sequence.
Inventory — anything sitting and waiting. Stock, yes, but also a queue of unprocessed emails, a backlog of unreviewed applications.
Motion — moving people. Reaching, walking, searching. Distinct from transport: this is the person, not the product.
Waiting — work that exists but nothing is happening to it. Usually the single largest category, and usually unmeasured.
Over-production — making more, or sooner, than the next step needs. It looks like productivity and it creates inventory.
Over-processing — more work than the customer's requirement calls for. A tolerance tighter than the specification. A report nobody reads.
Defects — anything requiring rework, correction or scrap. A defect costs you the original work and the correction.
Unused talent — the person doing the job knows exactly what is wrong with it and has never been asked.

The mnemonic TIM WOOD covers the original seven; add S for the unused skills of the eighth and it becomes TIM WOODS. Use whichever you like. The mnemonic matters far less than the habit of walking a process and asking, at each step, which of these am I looking at?

One caution before you start counting. A category is a prompt, not a verdict. Labelling a step "waiting" tells you where the time went; it does not tell you whether the wait can be removed, and it certainly does not tell you whose fault it is. Waste is a property of the process, not of the people inside it. A waste walk that produces a list of individuals has gone wrong.

Worked example

Here is the picker, one order, thirty-three minutes.

Step	Minutes	What was happening
Collect pick list from printer	2	walking to the printer at the far end
Walk to aisle 4	3	the picker moving
Search for item — label faded	4	not where the system said
Pick item	1	the actual value-add
Walk to aisle 11	4	the picker moving
Wait for ladder (in use)	7	waiting
Pick item	1	the actual value-add
Re-scan — first scan rejected	2	rework
Walk to despatch	3	the picker moving
Queue at despatch desk	6	queuing

Now tag each step. Watch how the category changes what you would do about it:

Motion — collecting the pick list (2), searching for the faded label (4), and the three walks (3 + 4 + 3 = 10). Sixteen minutes of a person moving and hunting. Fixed by moving the printer, fixing the label, and slotting: putting fast-moving items near each other.
Transport — nothing. Transport moves the product, and on this order the product only moves in the picker's hands. Every one of those minutes is already counted as motion. An empty bucket is a result: there is no layout problem here that a different lorry would fix.
Waiting — the ladder (7) and the despatch queue (6) = 13 minutes. Fixed by a second ladder, or by not needing one.
Defects — the rejected scan (2). Fixed at the label, again.
Value-add — two picks, 2 minutes.

Two minutes of value in thirty-three. 6%.

Now look at the manager's proposal again. Two more pickers would add two more people each spending 94% of their time on waste, and would make the ladder queue and the despatch queue worse, because more people would be waiting in them. The faded label costs six minutes on its own and can be fixed this afternoon by one person with a printer.

That is what the categories buy you. Not a tidier vocabulary — a different decision.

Dataset: ds-warehouse-picking — the same data loads in the tool below, so you can reproduce every figure here yourself.

Your turn

Open the Waste Spotter with this observation loaded and tag each step yourself.

Two things worth trying:

Tag the despatch queue as inventory rather than waiting. Both are defensible — the totes are stacked up, and the picker is standing there. Notice that the category you choose points at a different fix.
Change Collect pick list from printer from waste to business-necessary — somebody does have to know what to pick. The waste total falls from 31 minutes to 29 and the value-add ratio does not move at all, because the denominator is still the whole thirty-three minutes. Reclassifying a step changes the report and changes nothing about the morning. Only removing the two minutes would, and no dropdown can do that.

Waste Spotter

practice

Classify every step. Apply the customer test each time — would they pay for this? Effort and skill are never the test.

Observed process steps, their durations, and their classification.
Step	Min	Classification	Waste category
Collect pick list from printer	2
Walk to aisle 4	3
Search for item — label faded	4
Pick item	1
Walk to aisle 11	4
Wait for ladder (in use)	7
Pick item	1
Re-scan — first scan rejected	2
Walk to despatch	3
Queue at despatch desk	6

Lead time

33 min

Value-add

0 min

Value-add ratio

Waste

33 min

10 non-value-add steps have no waste category. Categorising them is what turns "this is waste" into a specific thing you can change.

How this is calculated

Value-add ratio = value-add time ÷ total lead time. The denominator is the whole clock, including every wait — not the time the team was busy. That distinction is what separates “how busy were we?” from “how much of the customer’s wait was worth it?”

Value-add — The customer would pay for it, it changes the thing, and it is right first time.
Business-necessary — The customer would not pay for it, but you cannot stop doing it.
Waste — Everything else.

Source: Rother & Shook (1999), Learning to See; the eight wastes from Ohno (1988), Toyota Production System, Ch.3.

Transport — moving the product
Inventory — work sitting and waiting
Motion — moving the person
Waiting — work exists, nothing is happening to it
Over-production — more, or sooner, than the next step needs
Over-processing — beyond the customer requirement
Defects — rework, correction or scrap
Unused talent — the people doing the job were never asked

Check yourself

No hints. Wrong answers are explained, not softened.

A finance team produces a 40-page monthly report. Two of its recipients read only the summary page; the other four do not open it. Which waste is this primarily?

In the warehouse observation, the picker walks 10 minutes between aisles and spends 4 minutes searching for a mislabelled item. How should these be categorised?

A team completes a waste walk and presents a list of the three staff members whose steps contained the most waste. What is wrong with this?

Worth remembering

The eight wastes

Transport, Inventory, Motion, Waiting, Over-production, Over-processing, Defects, Unused talent. TIM WOODS — the S is for the skills the eighth one wastes.

Transport vs motion

Transport moves the PRODUCT. Motion moves the PERSON. Different fixes: layout versus workplace organisation.

Can you do this now?

Rate yourself honestly. We compare your rating with how you actually answered — the gap is more useful than either number alone.

I can name the eight wastes and give an example of each from a process I know.

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