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Part Four
Improvement
Figure 18.7 The four approaches on the two dimensions of improvement
on how operations should be improved. Six Sigma in particular has relatively little to say
about what is good or bad in the way operations resources are organized (with the possible
exception of its emphasizing the negative effects of process variation). Its concern is largely
the way improvements should be made: using evidence, using quantitative analysis, using the
DMAIC cycle, and so on. They also differ in terms of whether they emphasize gradual or rapid
change. BPR is explicit in its radical nature. By contrast TQM and lean both incorporate
ideas of continuous improvement. Six Sigma is relatively neutral on this issue and can be
used for small or very large changes.
Improvement techniques
All the techniques described in this book and its supplements can be regarded as ‘improvement’
techniques. However, some techniques are particularly useful for improving operations and
processes generally. Here we select some techniques which either have not been described
elsewhere or need to be reintroduced in their role of helping operations improvement
particularly.
Scatter diagrams
Scatter diagrams
Scatter diagrams provide a quick and simple method of identifying whether there is evidence
of a connection between two sets of data: for example, the time at which you set off for work
every morning and how long the journey to work takes. Plotting each journey on a graph
which has departure time on one axis and journey time on the other could give an indication
of whether departure time and journey time are related, and if so, how. Scatter diagrams
can be treated in a far more sophisticated manner by quantifying how strong is the relationship
between the sets of data. But, however sophisticated the approach, this type of graph