A time study measures how long a qualified operator takes to do an operation, adjusts it for the operator's pace, and adds allowances to get a standard time. It is the basis for SMV in factories that do not use a predetermined time system, and it is the quickest way to check whether an operation is running to its standard.
What you need#
- A stopwatch or time study app that records laps.
- A time study sheet with the operation, elements and cycle columns.
- Agreement with the supervisor and the operator. Explain what you are doing and why.
- A trained operator working at a steady pace with correct materials and a working machine.
Step 1: Define the operation and its elements#
Write down the operation and break it into elements: small, distinct parts with clear start and end points.
Example: Attach sleeve to body, overlock.
| Element | Start point | End point |
|---|---|---|
| 1. Pick up and align sleeve and body | Hand touches sleeve | Parts at presser foot |
| 2. Sew seam | Foot lowered | Seam end, thread chained off |
| 3. Aside to bundle | Chain cut | Hand back at bundle |
Elements make the study more accurate and show where time is spent. Handling often takes as long as sewing.
Step 2: Record the cycles#
Time each element over several cycles. Common practice for short garment operations is 10 to 20 cycles, with more cycles when the times vary a lot. Mark any unusual cycle (dropped part, thread break) and exclude it from the normal times, but note the reason; frequent interruptions are information too.
Step 3: Rate the operator's pace#
Performance rating compares the operator's observed pace with a defined standard pace (100). An operator working faster than standard is rated above 100; slower, below 100. Rating needs training and practice, and it is the most subjective part of time study.
Step 4: Calculate basic time#
Step 5: Add allowances#
Allowances cover personal needs, fatigue and small unavoidable delays (such as thread changes). They are added as a percentage:
Allowance percentages depend on the factory's policy and the nature of the work. Use your company's agreed values, and apply them consistently across operations.
Worked example#
Observed average times (minutes) over 12 good cycles:
| Element | Average observed | Rating | Basic time |
|---|---|---|---|
| Pick up and align | 0.120 | 95 | 0.114 |
| Sew seam | 0.210 | 100 | 0.210 |
| Aside | 0.050 | 95 | 0.048 |
| Total | 0.372 |
With a 15% allowance (example value): standard time = 0.372 × 1.15 = 0.428 minutes. This is the SMV for the operation.
Hourly output at 100% = 60 / 0.428 = 140 pieces.
Machine and handling time#
In sewing, time splits into machine time (the needle is sewing) and handling time (picking up, aligning, positioning, disposing). In many operations, handling is the larger part. Time study shows this split and points to method improvements: better bundle position, guides, folders and fewer repositionings. See motion study.
Common mistakes#
- Timing a new or struggling operator instead of a trained one.
- Too few cycles, so one fast or slow cycle distorts the average.
- Forgetting to rate, so the standard reflects the individual, not the job.
- Including interruptions in normal element times.
- Changing the method during the study.
- Not recording the conditions: fabric, machine, speed and attachments used. The standard only applies to those conditions.
For the wider context of method study and work measurement, see work study, and for building a garment SMV from operation SMVs see SMV calculation.
Related guides#
- What is SMV: what the standard time is used for.
- Bottleneck analysis: choosing stations for a capacity study.