Standardised work
Standardised work (standardized work in the Lean literature, also standard work) sets, for each station in a repetitive process, the best method known: the work elements, their order, their duration and the number of units in process. The Lean Enterprise Institute builds it on three elements: takt time, the pace of demand; the work sequence; standard work in process. The technique comes from the Toyota Production System. Taiichi Ohno held it to be the precondition of kaizen, continuous improvement in small steps: no standard, no kaizen. Training to the standard uses the Job Instruction method of the American Training Within Industry programme.
Goal
Standardised work describes, station by station, how a person performs a repetitive task. The work standard is the document posted at the station that carries this method.
The technique reduces the variation that comes from people. When everyone picks their own method, the Society of Manufacturing Engineers (SME) notes, the result becomes unpredictable and the flow breaks. The standard also shows at the station, the same day, any deviation from the sequence, the time or the work in process.
The standard gives every shift a common description of the process. It reduces injuries and fatigue. It eases the training of new operators and forms the baseline for improvement. A change of method is measured against a fixed method. Without a standard, an improvement is one more variant, applied sometimes and often ignored.
The technique matches headcount to the pace of demand and says who does what. It delivers the standard work documents: the standardised work chart posted at the station, the combination table when a machine runs on its own during a cycle, the job breakdown sheet used for training.
In the Control phase of a DMAIC project, it holds the gain: it locks in the new method at the station. A kaizen event ends when the team updates the standard.
Usage
When to use it
- Repetitive task with a stable sequence: the same elements recur for every unit, in sufficient volume.
- Result that depends on the person or the shift: the standard sets a common method.
- A kaizen event or DMAIC gain to hold: without an updated standard, the old method returns.
- New staff arriving: training starts from a written method rather than from copying a colleague.
- Setting up a single-piece flow cell: the standard sets how the steps are split under takt time.
- Demand that changes: recalculate takt time, then headcount and the split of the elements.
- High-volume office work: invoices, requests, insurance claims; the SME includes repetitive administrative work.
When not to use it
- Unstable process: breakdowns, absences, missing material; stabilise first with 5S and root cause analysis.
- Batch work between stations: the standard assumes single-piece flow; create the flow first.
- Every case different or judgement work: no sequence repeats; write the recurring decision rules in a decision table.
Description
The three elements
Takt time is the pace at which the process must produce to keep up with customer demand. It equals the available production time divided by demand: 480 minutes a day for 240 pieces give a takt time of 2 minutes. Takt is the German word for a bar in music. No person receives more work per unit than the takt time.
The work sequence is the order in which an operator performs their work elements within takt time. A work element is the smallest piece of work that can be handed to another person: opening an envelope, checking an amount. The sequence follows the person rather than the unit: the operator may touch several units during one cycle. The time a person takes to run through their sequence is their manual cycle time. It excludes the time during which a machine runs on its own.
Standard work in process is the smallest number of units in process that lets each person run their sequence without stopping. It counts the units inside a machine and those waiting at a marked location between two people. The unit a person holds in hand is not part of it. The SME treats it as a barometer. At the start and end of each day, the cell holds exactly the standard work in process. More units signal needless handling and storage. Fewer units signal a person who is waiting. In both cases the team leader sees the deviation without a calculation.
The preconditions
The SME sets three conditions. The station works in flow, one unit at a time. The sequence repeats: high variety remains possible if the units have similar work content, and the team then standardises a typical unit. Finally, a team leader owns the standard, understands it and leads its improvement.
The Lean Enterprise Institute (LEI) adds a condition of stable operations: the machines run, the people are present, the work is repeatable, the material is available. On an unstable process, the team writes a standard that the next breakdown makes wrong.
Building the standard
- Calculate takt time. Record daily demand and the net available time, excluding breaks and team meetings. An accounts payable department that receives 70 invoices a day and has 420 minutes available has a takt time of 6 minutes.
- Observe and time at the station. Break the work into elements. Measure each element over several cycles, with the person who does it. Separate manual time, walking and machine time. Use the time a trained person can repeat on every cycle.
- Set the sequence and split the elements. Divide the total work by takt time to get the headcount: 11 minutes of work per invoice at a takt time of 6 minutes gives 1.83, so two people. The SME gives each person one takt time of work. In this department, each of the two people receives 5.5 minutes, a little under one takt time.
- Set the standard work in process. Count the units needed between the people and in the machines so that nobody waits. Mark their location: a tray, a shelf, a software queue capped at that number.
- Write the documents. Fill in the LEI forms, then the job breakdown sheet for each difficult element. Keep one set of documents for each headcount the cell regularly runs with.
- Post and train. Post the standardised work chart at the station. Train each person with the Job Instruction method.
- Check daily and update. The team leader compares the work in process, the sequence and the cycle time with the standard. When takt time changes, the team leader redoes the split and the documents. The LEI reports that Toyota revises the takt time of a process every month and reviews it every ten days for small adjustments.
The standard work documents
The LEI describes three forms. Two further sheets add to them.
| Document | What it carries | Who uses it and when | In an office without machines |
|---|---|---|---|
| Process capacity sheet | Machine cycle time, tool-change intervals and manual times of each machine in a sequence of stations | The team building the standard, to find the bottleneck | Not needed |
| Combination table | Manual time, walking and machine time of each operator, element by element | The team leader, to recalculate each person's work when takt time changes | Useful when a scanner or automated processing runs on its own |
| Standardised work chart | On the station layout: the operator's route, the location of the units, takt time and cycle time, the sequence, the standard work in process | The person at the station, where it is posted; the team leader, who checks it daily and revises it at every change | Useful |
| Work standards sheet | The technical requirements of the product that the station must meet | The person at the station | Useful |
| Job breakdown sheet (also job instruction sheet) | The important steps, their key points and their reasons | The trainer, during Job Instruction training | Useful |
Training to the standard: the Job Instruction method
The Training Within Industry (TWI) programme began in the United States during the Second World War. It helped companies train large numbers of workers who replaced the men called up. It had three programmes: Job Instruction to teach a job, Job Methods to improve it, Job Relations to handle problems between people. After the war the United States forgot it, and Japanese companies, Toyota among them, adopted it. Job Instruction remains the training tool of Toyota's team leaders worldwide.
The trainer prepares the learner and describes the task. The trainer then presents the job and shows each step. The learner performs the task in front of the trainer, as a trial. The trainer follows up and tapers off support until the learner works alone. NIST names these steps Preparation, Presentation, Test and Follow up.
The trainer prepares a job breakdown sheet in three columns: the important steps, what to do, in order; the key points, what makes the step succeed or fail; the reasons for each key point. The trainer uses it as a personal aid and presents the job one step at a time, at the learner's pace. This sheet links training to the standard: the steps follow the sequence, the key points carry the checks.
| Important step | Key points | Reasons |
|---|---|---|
| 1. Open the purchase order | Search by the order number printed on the invoice, never by the supplier's name | A supplier often has several open orders |
| 2. Compare the quantities | Invoiced quantity less than or equal to the quantity received, line by line, from the goods receipt | The company pays only for what has arrived |
| 3. Compare the prices | Tolerance 2%; above that, block the invoice and notify the buyer | The order price binds the supplier |
| 4. Hand over | Place the invoice in the transfer tray. If the tray still holds the previous invoice, alert the team leader | A pile in the tray hides a delay at the next station |
The standard and kaizen
"Without a standard, there is no kaizen." The LEI attributes the sentence to Taiichi Ohno, and the SME quotes it as "without standards, there can be no improvement". The standard sets the starting level. Managers set a target against that level. When the team achieves a measured gain, it updates the standard, or the gain disappears. The new standard becomes the starting point of the next improvement.
The team improves the standard. The team leader keeps its documents up to date. The team leader can do the job: they train new staff and stand in for an absent person. The team's proposals go through a kaizen board. Each deviation from the standard starts a short PDCA cycle.
Pitfalls
Writing the standard at a desk. A standard drafted without observing the station describes work that does not exist. The team works around it from day one. The team times the work at the station, with the people who do it.
Taking the best time. A time reached once by the fastest person overloads every station. The queue grows in front of the station and the team drops the standard. The team uses a time it can repeat on every cycle, and each load stays under takt time.
Confusing the standard with the quality procedure. A work instruction that lists requirements states neither the order, nor the time, nor the work in process. The work standards sheet sets the requirements; standardised work sets the method.
Freezing the standard. A standard that nobody revises blocks the team's improvements; the team stops proposing them. Conversely, a gain that never enters the standard is lost the first time someone leaves or a new person joins.
Ignoring the work in process. The standard sets two units in the cell and the team leader counts six without reacting. The barometer no longer works. A deviation in work in process triggers a search for the cause the same day.
Assessing people against the standard. The standard measures the method. Used to rank individuals, it pushes everyone to hide the deviations the technique exists to make visible.
AI considerations
A video of several cycles, filmed at the station with the team's consent, feeds an analysis tool that breaks the work into elements and measures their times. The event log of task-management software gives, for each case, the time each step started and ended: a process mining tool derives the cycle times and the actual work in process from it. A language model that receives the elements, their times and the takt time proposes splits between the people. It drafts a first job breakdown sheet from the standard. It translates the standard into the languages spoken at the station: French, German, Portuguese or Albanian.
The tool does not know the key points. The knack that makes a step succeed comes from the experienced person, and a model that guesses it invents it. The team leader checks each key point and each reason at the station. The log sees neither the walking, nor the paper pile, nor the call to a colleague: the team still times the work on site. The analyst recalculates each proposed split against takt time, in the spreadsheet.
Video and logs record people. Art. 26 of Ordinance 3 to the Employment Act (OLT 3) prohibits systems intended to monitor the behaviour of workers at their workstation. Art. 328b of the Code of Obligations limits the data an employer processes about a worker to data that concern their suitability for the job or that are necessary to perform the employment contract. The team aggregates times per element rather than per person. It deletes the videos once the times are recorded.
Examples
Standardised work chart of an accounts payable cell: 70 paper invoices a day, 420 minutes available, takt time of 6 minutes. Two people share seven manual elements; the scanner performs the eighth.
| No. | Work element | Person | Manual (min) | Walking (min) | Machine (min) | Quality check |
|---|---|---|---|---|---|---|
| 1 | Open the envelope, place the invoice on the scanner, start the scan | A | 0.5 | 0.5 | ||
| 2 | Scanning and automatic reading (OCR) | scanner | 3.0 | |||
| 3 | Check the header as read: supplier, UID number, IBAN | A | 1.5 | yes | ||
| 4 | Match the invoice to the purchase order and the goods receipt | A | 3.0 | yes | ||
| 5 | Check the VAT: rate (8.1%, 3.8% or 2.6%) and amount | B | 1.5 | yes | ||
| 6 | Post: account and cost centre | B | 2.0 | |||
| 7 | Above CHF 5'000, send for approval by the budget holder; otherwise release for payment | B | 1.0 | |||
| 8 | File the original | B | 0.5 | 0.5 | ||
| Cycle time | A 5.5 · B 5.5 · takt time 6.0 · total work 11.0 | |||||
| Standard work in process | 2 invoices: one in the scanner, one in the transfer tray | |||||
The scanner's three minutes count toward no one's cycle time: A starts the scan of the next invoice, then checks the one the scanner has just read. Total work is 11 minutes per invoice, or 770 minutes for 70 invoices, against the 840 minutes of the two people. If A finds the tray still full, B has fallen behind. If B finds it empty, A has fallen behind.
Visualisations
The standardised work chart places the example cell on its layout: the routes of A and B, the numbered elements, the two invoices of the standard work in process and the checks. The balance chart stacks each person's elements against the takt time line. The standard-and-kaizen diagram shows a gain that holds because the team updated the standard. The standard work documents, the job breakdown sheet and the list of elements are tables.
Cost
| Phase | Level | Justification |
|---|---|---|
| Preparation | Medium | Stabilise the process, calculate takt time. Time each element over several cycles, at every station, with the team's consent: a long observation, often unwelcome in office work. |
| Execution | Medium | Split the elements, set the work in process, train each person with Job Instruction. |
| Documentation | High | One set of documents per station and per headcount, posted and revised at every change of takt time or method. |
Tools
A stopwatch and an observation sheet are enough to record times at the station. A spreadsheet holds the elements, takt time, the cycle times and the split; it recalculates headcount when demand changes. The three LEI forms print out and are filled in by hand. An operator balance chart (yamazumi) stacks each person's elements against takt time.
The standard work documents hang in the cell, on a standardised work board. In the office, the task-management software carries the standard work in process: a queue capped at one invoice, in other words a WIP limit, replaces the transfer tray. Digital work instruction software displays the sequence at the station with photos and videos and keeps the version history. It pays off when the standard changes often or the station has many variants.
Sources
- Taiichi Ohno, Toyota Production System: Beyond Large-Scale Production, Productivity Press, 1988 (Japanese original, 1978): the Toyota Production System, where standardised work was born.
- Lean Enterprise Institute, Standardized Work, Lean Lexicon: the definition, the three elements, the benefits, the three forms, the work standards sheet and the job instruction sheet.
- Lean Enterprise Institute, Takt Time, Lean Lexicon: the calculation of takt time and its monthly revision at Toyota.
- Lean Enterprise Institute, Kaizen, Lean Lexicon: the definition of kaizen, Ohno's sentence on the standard and kaizen, the condition of stable operations, the update of the standard after a gain.
- Lean Enterprise Institute, Training Within Industry (TWI), Lean Lexicon: the origin of the programme, its three parts, its adoption by Toyota, the four steps of Job Instruction and the job breakdown sheet.
- SME, Standardized Work: the work sequence and manual cycle time, one takt time of work per person, standard work in process as a barometer, the preconditions, the roles of the team and the team leader.
- National Institute of Standards and Technology, Manufacturing Extension Partnership, Training Within Industry (TWI): the four steps of Job Instruction.
- Ordinance 3 to the Employment Act (OLT 3), SR 822.113, art. 26: the prohibition of systems intended to monitor the behaviour of workers at their workstation.
- Code of Obligations (CO), SR 220, art. 328b: the limitation of processing a worker's data to their suitability for the job or to the performance of the employment contract.