# Time Observation Sheet

**URL:** https://kaizumi.com/dictionary/time-observation-sheet

**Description:** A Time Observation Sheet (TOS) records repeated cycle times for each work element to establish the lowest repeatable time used in standardized work.

**Category:** lean-tools

**Tags:** metrics, quality, foundational

## Definition

The Time Observation Sheet (TOS) is the raw-data form used to capture repeated cycle times during a lean time study. An observer records at least ten cycles for each work element, then identifies the lowest repeatable time — the shortest time that an experienced operator achieves consistently, excluding outlier fast cycles and slow cycles caused by abnormalities. This lowest repeatable time becomes the manual-time input for the Process Capacity Sheet and the Standardized Work Combination Table. Unlike traditional time study, the TOS is not used to set quotas; it is used to reveal variation, expose problems, and establish honest baselines for kaizen.

## Examples

### Manufacturing

> An assembly team ran a TOS across ten cycles at a welding station. Element 4 showed times of 18, 22, 19, 47, 20, 18, 21, 19, 20, 18 seconds. The 47-second cycle was investigated and traced to a jammed fixture, a genuine abnormality worth addressing. The lowest repeatable time was 18 seconds, which the team used as the planning time for standardized work.

### Healthcare

> A lab ran a TOS on the specimen receiving process. The data showed that element 3 (barcode labeling) averaged 12 seconds but ranged from 8 to 45 seconds. The wide spread pointed to inconsistent label printer placement — a 5S problem — rather than operator variation, changing the improvement target.

### Administrative

> A claims office used a TOS on the intake-screening process. The sheet revealed that verification of prior claims consistently took three times longer than any other element. Eliminating a redundant database check halved that step's time.

## Key Points

- Capture at least ten consecutive cycles per element for meaningful variation data
- Record every cycle, including unusually long ones — outliers reveal problems
- The lowest repeatable time (not the average) is the input for standardized work
- Observe at the gemba, not from video or memory

## Common Misconceptions

**The TOS is used to find the fastest operator and set their time as the standard.** Standardized work is built from the lowest repeatable time achieved by a trained operator, not a one-off sprint. The goal is a realistic, sustainable pace — not a personal best.

**The TOS is a stopwatch-and-clipboard relic replaced by sensors and software.** Automated timing captures cycle data but misses the observer's context — why the 47-second cycle happened, what the operator noticed, which abnormalities are worth fixing. The human observation is the value, not the stopwatch.

## Try It

Run your own study right here. Record ten cycles per element, identify the lowest repeatable time, and export a print-ready form. (Also available as a [standalone tool](/tools/tos).)

<!--TOOL:tos-->

## See Also

- [Time Study](/dictionary/time-study) — The broader methodology
- [Cycle Time](/guides/cycle-time-vs-takt-time-vs-lead-time) — What the TOS measures
- [Standard Work](/dictionary/standard-work) — What the TOS feeds
- [Process Capacity Sheet](/dictionary/process-capacity-sheet) — Uses TOS data for manual time input

Source: https://kaizumi.com/dictionary/time-observation-sheet
Licence: free to quote and cite with attribution to Kaizumi.