The Lost Art of Activity Sampling
Activity Sampling and more over Time Study Techniques seem to be a lost art within Manufacturing nowadays. I was taught everything comes down to time, and we need to look at the most efficient way we use that time in everything we do.
Activity Sampling for me, is one of those essential tools that you keep in your back pocket, a fantastic technique that enables to economically study a lengthy activity or a group of activities producing statistically accurate data.
What is Activity Sampling?
Over a period of time a group of machines, processes or people can be observed at regular intervals to record what activities are being undertaken. Each observation records what’s happening at that particular time, this then builds to measure a percentage of time that activity occurs thought-out the hour, day, etc.
This technique is particularly useful to estimate the proportion of Value-Added Time to Non Value-Added time that occurs within your business processes. Example observations could be machine breakdowns, moving material, change-overs, waiting, Operating, filling in paperwork, etc. These examples are more aligned to the manufacturing operations point of view, but it is as equally as important in back-office processes and even looking at your own internal time-wasting activities to raise personal productivity.
An Example Activity Sampling in Action
In this example three people/processes are being activity sampled regarding ‘packing’, the activity was completed over a 2 hour period with observations every 2 minutes. The results are shown in the images below.
The above images illustrate the allocated percentages of each activity, we can now start to analyse to see what improvements can be made to work smarter (NOT HARDER), this can go hand in hand with spaghetti diagram to illustrate material and person movement, more detailed time Study work and process mapping.
You ‘ll notice that Packing Process 2 has no computer time in the two hours, as we analyse and ask around the variation, Process Packing 2 batches all of their paperwork up first and then processes it in one hit. Activity sampling would have picked this out even if we had of observed it, as the observation percentage compared to the other two processes would have been higher.
- It gives unbiased result.
- lts study may be interrupted at any time without affecting the results.
- It can be conducted by anyone with limited training.
- Team work can be studied by activity sampling.
- It is economical and less time consuming than time study.