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Operations Management and Strategic Management · Designing of Operational Systems and Control

Method Study and Work Measurement for CMA Intermediate

Updated 10 October 2026 · Fact-checked

Method study records and critically examines how a job is done, to find a simpler, better method. Work measurement then finds the time a qualified worker needs for that method. Standard time = Normal time + Allowances, where Normal time = Observed time × Rating ÷ 100. Use it to set targets and improve productivity.

Understand Work Study: Method Study and Work Measurement

Work study has two parts. Method study asks: how is the job done, and can it be done better? Work measurement asks: how long should the job take when done by the better method? Method study comes first, because there is no point timing a wasteful method.

Method study follows a set procedure, often remembered as SREDIM: Select the job, Record the present method (process charts, flow diagrams), Examine it critically (what, why, where, when, who, how), Develop the best method, Install it, and Maintain it. The examine step asks for each activity whether it can be eliminated, combined, rearranged or simplified.

Work measurement sets the standard time. The main techniques are time study (stopwatch readings of a job, element by element), work sampling (many random, instant observations of whether a worker or machine is busy or idle), synthesis from standard data, and predetermined motion time systems. Time study suits short, repetitive jobs. Work sampling suits long, irregular jobs and finding idle time.

In time study, the observer takes the observed time, adjusts it by a rating (the observer's judgement of the worker's pace against a standard of 100) to get normal time, then adds allowances for fatigue, personal needs and unavoidable delays to get standard time. Standard time is used for wage incentives, costing, planning and capacity decisions.

The difference is simple. Method study improves how work is done and cuts effort and waste. Work measurement fixes how much time the work should take.

Key rules to remember

Normal time
Normal time = Observed time × Rating ÷ 100
Use the average observed time per element. Rating of 100 is standard pace; above 100 means a faster worker.
Standard time (allowance on normal time)
Standard time = Normal time + Allowances = Normal time × (1 + allowance %)
Use when the allowance is given as a percentage of normal time.
Standard time (allowance on total time)
Standard time = Normal time ÷ (1 − allowance %)
Use when the question says allowance is a percentage of the standard (total) time.
Work sampling: percentage of activity
Activity % = Observations of the activity ÷ Total observations × 100
Observations must be random and numerous for the result to be reliable.
Method study procedure
SREDIM: Select, Record, Examine, Develop, Install, Maintain
Write the steps in this order in theory answers.

How to solve Work Study: Method Study and Work Measurement questions

Use this approach for any question on work study, whether theory or numerical.

  1. 1Identify whether the question is on method study (improving the method) or work measurement (setting time).
  2. 2For theory, write the SREDIM steps in order and add one line on each, with a short example.
  3. 3For a time study sum, find the average observed time for each element, or use the time given.
  4. 4Convert to normal time using the rating: observed time × rating ÷ 100.
  5. 5Read the allowance wording carefully. Decide whether it is on normal time or on total time.
  6. 6Compute standard time with the matching formula.
  7. 7If asked, convert standard time to output per hour or per shift, or to labour cost per unit.
  8. 8State the result with units and one line of interpretation, such as the target output or incentive base.

Quickest way: Observed to standard time in three lines

When to use it: Use for numerical questions that give observed time, rating and allowances.

  1. Normal time = Observed × Rating ÷ 100.
  2. Check the allowance basis: normal time means multiply by (1 + %); total time means divide by (1 − %).
  3. Standard time = result. Units per hour = 60 ÷ standard time in minutes.

Common mistakes in Work Study: Method Study and Work Measurement

  • Adding allowances to observed time instead of normal time

    Students skip the rating step when it looks like an extra calculation.

    Fix: Always rate first. Allowances are added only after normal time is found.

  • Using ×(1 + %) when allowance is stated on total time

    Both wordings look alike under pressure.

    Fix: If the allowance is a share of the standard time, divide normal time by (1 − %).

  • Writing method study steps out of order or missing Maintain

    Students remember Select and Record but forget the later steps.

    Fix: Learn SREDIM and write each letter with a one-line meaning.

  • Confusing method study with work measurement

    Both are parts of work study and are often taught together.

    Fix: Method study: how to do it. Work measurement: how long it takes. Method study comes first.

  • Applying the rating to the allowance or to the standard time

    Students are unsure where rating belongs in the sequence.

    Fix: Rating converts observed time to normal time only.

Worked examples

Example 1

A time study of a job gives an average observed time of 4.5 minutes per piece. The worker's rating is 120. Allowances are 10% of normal time. Find the standard time and the standard output in an 8-hour shift.

Show the solution
  1. Normal time = 4.5 × 120 ÷ 100 = 5.4 minutes.
  2. Allowance = 10% of 5.4 = 0.54 minutes.
  3. Standard time = 5.4 + 0.54 = 5.94 minutes per piece.
  4. Shift time = 8 × 60 = 480 minutes.
  5. Output = 480 ÷ 5.94 = 80.8 pieces, so about 80 complete pieces.

Answer: Standard time is 5.94 minutes per piece; standard output is about 80 pieces per 8-hour shift.

Example 2

Normal time for an operation is 8 minutes. Fatigue and personal allowances total 20% of the standard time. Find the standard time. Also, in a work sampling study of 400 random observations, a machine was found idle in 60. State the idle percentage.

Show the solution
  1. The allowance is on standard time, so Standard time = Normal time ÷ (1 − 0.20).
  2. Standard time = 8 ÷ 0.80 = 10 minutes.
  3. Check: 20% of 10 = 2 minutes; 8 + 2 = 10, which agrees.
  4. Idle % = 60 ÷ 400 × 100 = 15%.

Answer: Standard time is 10 minutes; the machine was idle 15% of the time.

Exam tips

  • In Section A, expect one-line checks such as the order of SREDIM, or what work sampling is used for. Learn definitions precisely.
  • In numerical questions, show the three stages: observed, normal, standard. Step marks are given for each.
  • Underline the allowance wording in the question before choosing a formula.
  • For theory, add a short practical example, such as a packing line, to lift a plain list into a good answer.

Practice questions from Designing of Operational Systems and Control

Work Study: Method Study and Work Measurement: frequently asked questions

What is the difference between method study and work measurement?

Method study finds the best way to do a job by recording and examining the present method. Work measurement finds the time a qualified worker needs for that method. Method study is done first.

What are the steps in method study?

The steps are Select, Record, Examine, Develop, Install and Maintain, remembered as SREDIM. Each step builds on the one before it.

How do I calculate standard time?

Find normal time as observed time × rating ÷ 100. Then add allowances. If the allowance is on normal time, multiply by (1 + %). If it is on total time, divide by (1 − %).

When is work sampling better than time study?

Work sampling suits long or irregular jobs and studies of idle time, since it uses many random observations. Time study suits short, repetitive jobs timed with a stopwatch.