It is particularly important that students come to understand the nature of variation in process performance and how it can affect quality. We have found that the best way to do this is to devise games to demonstrate the choices that need to be made when dealing with variability.

Fortunately, it is not difficult to devise games of this sort. Here are two options.

• Game 1 – Find some easily available product that contains pieces, supposedly of the same size. We use the small wooden blocks that are used in some children’s building sets and games. Instruct groups of students to measure successive blocks using a micro-measuring device (available at specialist and hardware stores). Get them to plot on an SPC chart the variation in the size of the blocks and from that calculate the central and control limits for mean and range.

• Game 2 – Do something similar, but select an Internet search site such as one that searches for cheap flights or hotel accommodation. Get the students to time the variance in response time and calculate limits as before. The advantage of this approach is that one can ask students to sample from the same site at different times to check whether the process is getting out of control.

• Game 3 – Use a short case study (an appropriate one is shown at the end of this section) and ask the students to draw process charts. Then show them new data, period by period, and ask them to tell you when the process goes out of control.