How To Do A Time Study: The Complete Industrial Engineering Guide
A time study is a structured work measurement technique used to record the times and rates of working for the elements of a specified job, operating under specified conditions, to determine the standard time necessary for an operator to perform it at a defined pace. By systematically analyzing cyclical operations using precision timing equipment and performance rating adjustments, organizations eliminate production bottlenecks, optimize labor standards, and accurately forecast capacity.
Pre-Operation & Planning Checklist
Executing an effective time study requires rigorous preliminary planning to minimize operational disruption, secure accurate baseline data, and ensure operator cooperation. Industrial engineers must establish a clear scope of work, communicate the objectives clearly to the workforce to prevent anxiety, and select operations that offer sufficient repetition and high economic impact.
- Essential gear, tools, and software: Dual-action mechanical stopwatch or digital time study board, specialized time study observation sheets or industrial engineering mobile software, clipboard, calibrated high-definition video camera (optional for secondary review), and a calculator.
- Mandatory prerequisite knowledge and standards: Familiarity with industrial ergonomics, predetermined motion time systems (PMTS), standard stopwatch timing methods (cumulative vs. flyback), and performance rating calibration techniques such as the Westinghouse system.
- Estimated budget and duration benchmarks: Zero to minimal direct equipment cost if utilizing manual stopboards; software licenses range from five hundred to three thousand dollars annually. A typical study requires two to four hours of preliminary cycle observation per job complexity level, followed by two hours of data normalization and calculation.
Step-by-Step Time Study Execution Workflow
Step 1: Define and Break Down the Operation into Elements
Isolate the specific production task and divide the work cycle into discrete, measurable components known as elements. Each element must possess a clearly defined, observable start and stopping point, known as break points, to allow the analyst to record distinct timestamps. Keep manual handling elements separate from machine-controlled elements to ensure accurate variance tracking.
Pro-Tip: Keep individual element durations between 0.04 minutes and 0.10 minutes where possible; extremely short elements lead to observation recording errors, while overly long elements mask micro-inefficiencies.
Step 2: Select the Operator and Record Operating Conditions
Choose an experienced, fully trained operator who performs the job at a normal, consistent pace—avoiding workers who are exceptionally fast or exceptionally slow. Document all environmental and operational parameters on the observation sheet, including ambient temperature, machine settings, raw material lot numbers, and specific tooling used, to ensure the study can be replicated.
Warning: Never conduct a time study on a newly trained operator or during an unrepresentative production run involving sub-par raw materials, as this permanently skews standard labor rates.
Step 3: Conduct the Observations and Capture Raw Times
Observe the operator across multiple complete work cycles while recording the time elapsed for each individual element. Utilize the flyback timing method to reset the stopwatch to zero at the end of every element, or the continuous method to capture cumulative elapsed time without resetting the watch, which prevents missing short interval occurrences.
Step 4: Apply Performance Rating Adjustments
Evaluate the operator's actual working pace during each cycle relative to the company's established standard of normal performance, often benchmarked at 100 percent. Multiply the average observed time by this performance rating factor to yield the basic time, neutralizing the impact of working exceptionally fast or slow during the observation window.
Step 5: Calculate Allowances and Determine Standard Time
Add standard allowances to the basic time to account for personal needs, unavoidable fatigue, and operational delays, typically ranging between 10 to 20 percent of the total cycle time. Combine the adjusted basic time with these calculated allowances to arrive at the final standard time required for scheduling, costing, and line balancing.
Process Time Study Template
Comparison of Time Study Timing Methods and Metrics
| Parameter / Metric | Flyback Timing Method | Continuous Timing Method | Predetermined Motion Time Systems |
|---|---|---|---|
| Primary Advantage | Immediate direct reading of elemental times without subtraction. | Zero risk of missing split seconds between rapid cyclical transitions. | No operator observation required; establishes time prior to production. |
| Primary Limitation | Watch lag during the snapback motion can introduce recording errors. | Requires extensive post-study mathematical subtraction for every element. | Highly theoretical; requires deep specialized training and costly databases. |
| Ideal Application | Long-cycle, highly repetitive manual assembly operations. | Short-cycle, high-speed manufacturing where elements flow rapidly. | New product lines where physical prototyping is unavailable or restricted. |
Common Site Failures and Field Fixes
- Hawthorne Effect Distortions: The operator artificially alters their natural pace due to the overt presence of the industrial engineer holding a clipboard.
- Root Cause: Lack of transparency and trust between management, the floor workforce, and the analyst.
- Actionable Fix: Conduct comprehensive briefing sessions prior to the study, involve union representatives or lead operators in the observation process, and utilize discreet observation methods or fixed cameras when permissible.
- Inconsistent Element Break Points: The analyst records fluctuating times because the physical boundary markers of an element are poorly defined.
- Root Cause: Ambiguous operational definitions and lack of strict procedural documentation.
- Actionable Fix: Rewrite the standard operating procedure with explicit visual break points, such as the exact moment a bolt enters a threaded hole, and retrain observation personnel.
- Insufficient Sample Size: The calculated standard time contains a high margin of error due to recording too few operational cycles.
- Root Cause: Rushing the data collection phase to meet tight engineering deadlines.
- Actionable Fix: Apply statistical sample size formulas utilizing desired accuracy levels (typically within 5 percent error at a 95 percent confidence interval) to dictate the mandatory minimum number of cycles.
Frequently Asked Questions
How many cycles should I observe during a time study?
The required number of cycles depends on the cycle time duration, process variability, and desired statistical confidence level. Analysts typically utilize standard statistical tables based on desired accuracy and precision to determine whether ten, thirty, or over one hundred cycles are necessary to achieve a reliable standard.
What is the difference between normal time and standard time?
Normal time is the time required for a qualified operator to complete a task at a normal working pace without allowances. Standard time is the final calculated figure derived by adding specific allowances for personal fatigue, unavoidable delays, and basic needs to the normal time.
How do machine-paced elements affect time studies?
Machine-paced elements require no performance rating adjustment because the speed is controlled entirely by mechanical limits rather than operator effort. Analysts measure the machine cycle time accurately and apply minimal or zero rating factors to those specific machine-controlled elements.
What are allowances in a time study?
Allowances are percentage additions applied to the basic time to account for unavoidable interruptions, worker fatigue resulting from physical exertion or environmental strain, and personal biological breaks. These allowances ensure that production standards remain realistic and sustainable across a full work shift.
Transform your facility's operational efficiency and labor accuracy by implementing standardized time studies across your production lines today. Connect with our industrial engineering experts to discover advanced work measurement software solutions tailored to your manufacturing environment.
