Work sampling or activity sampling is a method of finding the percentage occurrence of certain activity by statistical sampling and random observations.

Advantages of work sampling

1. Many operators or activities which are difficult or uneconomical to measure by time study can readily be measured by work sampling.
2. Two or more studies can be simultaneously made of several operators or machines by a single study person.
3. It usually requires fewer man-hours to make a work sampling study than to make a continuous-time study.
4. The cost may also be about a third of the cost of a continuous-time study No stopwatch or other time measuring device is needed for work sampling studies.
5. It does not need any timing device such as a stopwatch.
6. It usually requires less time to calculate the results of a work sampling study.

Disadvantages of Work Sampling

• Work sampling does not measure the time required to perform some sequence of activities.
• Work sampling does not permit a fine breakdown of activities and delays such as is possible with time study.
• Accuracy of work sampling studies are based on the subjective assessment and perception of the analyst
• Results could be uneven from study to study.
• Difficult to conclude if the worker is working or not.
• This brings in inaccuracy in the results.
• The study is limited to few workers.
• It is ineffective with short cycles. It does not provide a complete breakdown of elements as in the time study.
• Observers tend to follow a repetitive route of travel rather than following a random sequence of operations.
• The time of observations is predicted in a way to influences the results.
• Work sampling gives misleading results if the system is in the process of change. The basic assumption in the work sampling technique is that all the observations are made to pertain to the same static system.