Operations Management and Strategic Management · Control Measures - Time and Motion Study, Method Study, Work Study

Recording Techniques and Process Charts in Method Study

Updated 10 October 2026 · Fact-checked

Recording techniques are the charts and diagrams used in method study to write down the present way of doing a job, so it can be examined and improved. Choose the tool by purpose: process charts for sequence, diagrams for movement paths, activity charts for worker and machine timing, SIMO charts for hand motions.

Understand Recording Techniques and Process Charts

Method study follows a set sequence: select the job, record the present method, examine it critically, develop a better method, install it and maintain it. Recording is the second step. You cannot improve what you have not written down in full.

Recording works best when it uses standard symbols and charts rather than long descriptions. A chart shows every step, delay and movement at a glance, so wasted effort becomes easy to spot.

The tools fall into three groups. Process charts show the sequence of events: the operation process chart and the flow process chart. Diagrams show movement on a floor plan: the flow diagram and the string diagram. Time-scale charts show who or what does what, and when: the multiple activity chart and the SIMO chart.

The operation process chart (outline process chart) shows only operations and inspections for the whole product, including all components and assemblies. The flow process chart is more detailed. It adds transport, delay and storage. It comes in three types: man type (what the worker does), material type (what happens to the material) and equipment type (how equipment is used).

A flow diagram is a scaled layout drawing with the path of movement of men or materials marked on it, using the process chart symbols. A string diagram uses a thread run around pins on the layout to show the paths of a worker or material. The total thread length, measured against scale, shows the distance travelled. Both show backtracking, crossing paths and long travel.

A multiple activity chart records the activities of several subjects (workers, machines) against a common time scale, so idle time of each shows up. A SIMO chart (simultaneous motion cycle chart) records the hand, arm and body movements of one operator on a common time scale, using therbligs. It is a micro-motion tool, used for short repetitive jobs.

Key rules to remember

Operation: Symbol: circle (○); Value-adding step where material is changed or assembled. Also used for preparing or giving information.
Transport: Symbol: arrow (→); Movement of worker, material or equipment from one place to another, except during an operation.
Inspection: Symbol: square (□); Checking quality or quantity against a standard.
Delay (temporary storage): Symbol: D; Unplanned wait where the next step cannot start immediately.
Storage (permanent): Symbol: inverted triangle (▽); Material is held and needs authorisation to be issued.
Combined activity: Symbol: circle inside a square (⊙ in □); Operation and inspection done together by the same person at the same place.
Chart choice rule: Sequence → process charts; path of movement → flow or string diagram; timing of several subjects → multiple activity chart; hand motions → SIMO chart; Use this to pick the tool in any question.
Machine utilisation on activity chart: Utilisation % = Machine working time ÷ Cycle time × 100; Applies to a multiple activity chart where the cycle time is the same for every subject.

How to solve Recording Techniques and Process Charts questions

Use this method for definition, differentiation and chart-drawing questions alike.

1Read what is asked: define a tool, compare two tools, draw a chart or suggest an improvement.
2Identify the purpose: sequence, path of movement, timing of workers and machines, or hand motions.
3Name the correct tool and say whether it is a process chart, diagram or time-scale chart.
4For a chart, list the steps in order and assign the correct symbol to each: operation, transport, inspection, delay, storage.
5For activity charts, draw a common time scale and mark working and idle time for each subject.
6Count or total: number of each symbol, distance, time, idle time, utilisation.
7Use the record to point to improvement: remove, combine, rearrange or simplify steps.
8State the conclusion in one line, as ICMAI expects interpretation.

Quickest way: Purpose-to-tool shortcut

When to use it: Use for MCQs and short differentiation questions when you have under two minutes.

Spot the keyword: outline means operations and inspections only; flow means all five symbols.
Thread, pins or string means string diagram; scaled layout with lines means flow diagram.
Several workers or machines on a time scale means multiple activity chart.
Left hand and right hand, therbligs or micro-motions means SIMO chart.
Check the symbols against the definition before choosing an option.

Common mistakes in Recording Techniques and Process Charts

Showing transport, delay and storage in an operation process chart.
Students mix the outline chart with the flow process chart.
Fix: Remember that the operation process chart has only operations and inspections. Flow process chart adds the other three.
Calling a flow diagram and a string diagram the same thing.
Both are drawn on a layout and show movement.
Fix: A flow diagram draws the path as lines with symbols. A string diagram uses thread to measure the distance and frequency of movement.
Treating a SIMO chart as a chart for several workers or machines.
Confusion with the multiple activity chart.
Fix: SIMO records the body parts of one operator. Multiple activity charts record different subjects.
Using the wrong symbol, for example a circle for movement of a trolley.
Symbols are memorised without meaning.
Fix: Learn each symbol with its meaning. Movement between places is always transport.
Drawing a chart but giving no improvement comment.
Students think recording is the whole answer.
Fix: End with one or two lines on what can be eliminated, combined or rearranged.

Worked examples

Example 1

A flow process chart of a material records the following: raw material stored; moved to cutting section; cut; inspected; waited for the next batch; moved to the finishing section; finished; stored as finished goods. Count each symbol and state the number of non-value-adding steps from the list of transport, delay and storage.

Show the solution

List the steps with symbols: storage, transport, operation (cut), inspection, delay, transport, operation (finish), storage.
Storage (▽): 2 (raw material and finished goods).
Transport (→): 2.
Operation (○): 2.
Inspection (□): 1.
Delay (D): 1.
Transport, delay and storage together: 2 + 1 + 2 = 5.
Total steps: 2 + 2 + 2 + 1 + 1 = 8, which matches the list.

Answer: Operations 2, inspection 1, transport 2, delay 1, storage 2. Five of the eight steps are transport, delay or storage and are targets for elimination or reduction.

Example 2

In a multiple activity chart for one operator and one machine, the cycle time is 10 minutes. The operator loads the machine in 2 minutes, the machine runs on its own for 6 minutes, and the operator unloads in 2 minutes. The operator works only while loading and unloading. Find the machine and operator utilisation and comment.

Show the solution

Cycle time = 2 + 6 + 2 = 10 minutes.
Machine working time: the machine runs for 6 minutes. It is idle during loading and unloading, 4 minutes.
Machine utilisation = 6 ÷ 10 × 100 = 60%.
Operator working time = 2 + 2 = 4 minutes. Idle time = 6 minutes.
Operator utilisation = 4 ÷ 10 × 100 = 40%.
Comment: the operator is idle for 6 minutes, while the machine is idle for 4 minutes.

Answer: Machine utilisation is 60% and operator utilisation is 40%. The operator has 6 idle minutes per cycle, so assigning a second machine or other work should be considered, subject to the machine run time.

Exam tips

Learn the symbol set and meanings first, since many MCQs test only these.
In differentiation questions, give at least four points: purpose, detail, drawn on, and use.
When asked to draw a chart, use a neat table with step, symbol, distance and time columns, even if the question gives no format.
Always add an improvement comment after a chart or utilisation calculation to earn the interpretation marks.
Check that the total of each symbol equals the total of steps listed.

Practice questions from Control Measures - Time and Motion Study, Method Study, Work Study

Recording Techniques and Process Charts: frequently asked questions

What is the difference between a flow diagram and a string diagram?

A flow diagram is a scaled layout with the path of movement drawn on it using process chart symbols. A string diagram uses a thread around pins on the layout. The string diagram also helps you measure distance and see how often routes are used.

What is the difference between an operation process chart and a flow process chart?

The operation process chart shows only operations and inspections for the whole product. The flow process chart shows operations, inspections, transport, delay and storage in detail. It can be man type, material type or equipment type.

What is a SIMO chart used for?

A SIMO chart records the movements of different parts of one operator's body on a common time scale. It is used for short, repetitive jobs. It helps find ways to simplify motions and balance the work of both hands.

How is a multiple activity chart different from a SIMO chart?

A multiple activity chart covers several subjects such as workers and machines against time. A SIMO chart covers the micro-motions of a single operator. The first finds idle time of resources, and the second improves motions.