Definition: Work Sampling is a fact finding tool, based on laws of probabilities and based on Instantaneous and unbiased observations at random times. The main objective of work sampling is to determine productivity by using the proportion of activities observed to estimate the actual activities performed during working hours.

History: Work sampling, also referred to as "Activity Sampling" or "Ratio delay study", reflects a work measurement technique originally developed by L.H.C. Tippett in 1927. "Snap reading method" was the first term used, referring to its most important feature of taking activity snapshots. In 1941, R.L. Morrow introduced the methodology in U.S., using the "ratio delay study" terminology. In 1952, the "work sampling" term was first used by C.L. Brisley.

The method originated within the industrial engineering and management fields. Later on, the method was extended to health care industry and other areas. Today Work Sampling is one of the most appreciated work measurement methodologies because of the speed, low cost, limited training requirement and accuracy.