Work sampling does not involves stopwatch measurement as do many of the other techniques instead it is based on simple random sampling techniques derived from statistical sampling theory. The purpose of the sampling is to estimate what proportion of a worker time is devoted to work activates. A work measurement techniques that involves defining the state of "working observing the job over time and computing the portion of time the worker is working."Work sampling is also known by the following names:
a. Activity sampling
b.Ratio delay
c. Snap reading methods of observing.
According to British Standards institute " A techniques in which a large number of instantaneous observations are made over a period of time of a group of machines, process or workers. Each observation records what is happening at that instant and the percentage of observation recorded for a particular activity or delay is a measure of the percentage of time during which that activity or delay occurs.According to Mr. Tippet, " Work sampling as a method of finding the ration of delay and work element to the total process time by random observations."Work sampling thus involves the estimation of the proportions of time devoted to a given type of activity over a certain period of time by means of intermittent randomly spaced instantaneous observations.