7.13 Waste Analysis: The Seven Classic Wastes and Resource Under-Utilization
Key Takeaways
- The seven classic wastes are overproduction, inventory, defects, over-processing, waiting, motion, and transportation.
- Resource under-utilization, sometimes called non-utilized talent, is the eighth waste added to the classic seven.
- Overproduction is considered the worst waste because it generates inventory, waiting, transportation, and hidden defects.
- Value-added activity must satisfy three tests: the customer would pay for it, it changes the item, and it is done right the first time.
- Motion is movement of people; transportation is movement of material, information, or product.
Value-added and non-value-added
Every activity in a process falls into one of three classes.
| Class | Test | Treatment |
|---|---|---|
| Value-added (VA) | Passes all three tests below | Optimize |
| Business-non-value-added (BNVA) | Fails the customer test but is required by law, regulation, or a business necessity | Minimize |
| Non-value-added (NVA) | Fails all tests and is not required | Eliminate |
The three value-added tests:
- Would the customer be willing to pay for this activity?
- Does the activity physically change the product, service, or information toward what the customer wants?
- Is it done right the first time?
An activity must pass all three. Regulatory inspection in a medical device plant fails test 1 but is mandatory, so it is business-non-value-added: minimize it, do not eliminate it. Rework fails test 3 by definition and is always waste, however necessary it feels.
In most transactional processes, value-added time is under 10% of total lead time, which is why attacking the waiting and queuing is worth far more than speeding up the work itself.
The seven classic wastes
| Waste | Definition | Typical symptoms | Common causes |
|---|---|---|---|
| Overproduction | Producing more, sooner, or faster than the next process needs | Finished goods stock, batch running, "keeping the machine busy" | Large batch sizes, push scheduling, long changeovers |
| Inventory | Any material or information beyond the minimum needed | Raw, WIP, and finished stock; backlogs; queues; email in-trays | Overproduction, unreliable supply, long lead times |
| Defects | Output that does not conform, requiring rework, scrap, or repeat | Scrap, rework loops, returns, re-entered data | Process variation, unclear standards, poor MSA |
| Over-processing | More work, tighter tolerance, or more features than the customer requires | Multiple approvals, duplicate data entry, unnecessary precision | Unclear requirements, legacy procedures, no CTQ definition |
| Waiting | Idle time for people, material, or information | Queues, machine idle time, waiting on approvals or information | Line imbalance, unreliable equipment, batching |
| Motion | Unnecessary movement of people | Walking for tools, reaching, searching, excessive keystrokes | Poor layout, no 5S, badly designed screens |
| Transportation | Unnecessary movement of material, product, or information | Forklift trips, handoffs between departments, document routing | Poor layout, functional silos, centralized operations |
Mnemonics: TIMWOOD (Transportation, Inventory, Motion, Waiting, Over-processing, Overproduction, Defects), or DOWNTIME when the eighth waste is included.
Motion versus transportation
This distinction is a reliable exam question. Motion moves people; transportation moves things. An operator walking 30 metres to a tool crib is motion. A forklift carrying a pallet 30 metres to the next operation is transportation. In transactional processes, an analyst clicking through five screens to find a customer record is motion; routing a file to another department for approval is transportation.
Why overproduction is the worst
Overproduction is conventionally ranked the most damaging because it generates the others:
- It creates inventory, which needs space, handling, and capital.
- Inventory creates transportation and motion to move and find it.
- It creates waiting, because units queue for the next step.
- It hides defects, because a defect made early is not discovered until the batch is consumed, by which time hundreds of units share it.
The last point is the most consequential. Producing in large batches lengthens the feedback loop between making a defect and detecting it, which multiplies the cost of every process problem.
The eighth waste: resource under-utilization
The Body of Knowledge names resource under-utilization alongside the classic seven. It covers unused human capability: skills not applied, ideas not solicited, people assigned below their capability, and knowledge that stays with an individual.
Symptoms: an improvement suggestion scheme with no responses; operators who know exactly why the process fails and have never been asked; a trained Green Belt doing no project work; a single person who is the only one who can run a critical operation.
The waste is real and measurable through its consequences -- rediscovering known problems, longer problem-solving cycles, and turnover of skilled staff. It also under-utilizes non-human resources: equipment idle between campaigns, floor space, and licensed software nobody uses.
Conducting a waste analysis
- Walk the process at the gemba, following one unit end to end.
- Record every activity with its time and its class: VA, BNVA, or NVA.
- Tag each NVA activity with its waste category.
- Quantify, in time and money. "Motion" is an observation; "operators walk 4.2 km per shift, 38 minutes of paid time per operator per day" is a business case.
- Compute process cycle efficiency -- value-added time divided by total lead time -- to size the opportunity.
- Pareto the waste by time or cost, and attack the largest categories.
Two disciplines make the difference. First, time the activities rather than estimating them; teams consistently underestimate waiting and overestimate touch time. Second, look for the waste that generates other waste: eliminating one instance of overproduction often removes inventory, transportation, and waiting at the same time, which is why the value stream map is the right instrument rather than a step-by-step activity list.
Waste and the DMAIC phases
| Phase | Waste-related activity |
|---|---|
| Define | Identify obvious waste in the SIPOC; scope around a value stream rather than a department |
| Measure | Value stream map with VA/NVA classification; compute process cycle efficiency |
| Analyze | Waste analysis proper: categorize, quantify, and prioritize the NVA activity |
| Improve | Apply lean methods -- pull, kanban, 5S, SMED, standard work, poka-yoke |
| Control | Visual controls and standard work that prevent the waste from returning |
An operator walks 30 metres to a tool crib several times per shift, and a forklift moves pallets 30 metres between two operations. How are these classified?
Why is overproduction conventionally considered the most damaging of the seven wastes?
A medical device plant performs a regulatory-mandated final inspection that the customer would not choose to pay for. How should this activity be classified and treated?