Tip Sheet:
Cause and Effect Analysis Tool
1. Introduction
You have decided to improve the resource efficiency of your business and have
established a team to look at the key waste issues. You have established the key
areas for further investigation using a brainstorming session and undertaking a mass
balance to identify priority actions.
If your priority action is a process, you will need to break it down into component
tasks and look at where the wastes are occurring. Sometimes it is not easy to find all
the wasteful activities. Using a cause and effect diagram (sometimes called a
fishbone diagram) will help you identify all the possible causes. There is often more
than one cause for each effect. This diagram is a standard tool for quality
improvement and provides a useful record of the ideas generated.
2. Key stages
To create a cause and effect diagram for each key area, simply;
1. Start by writing the ‘undesired effect’, e.g. inefficient water use, to the righthand side of the diagram – this represents the head of the fish.
2. Now begin to identify the root causes of the effect, e.g. methods, and draw it
to the left – each root cause represents a main bone.
3. Taking each root cause (main bone) in turn, identify more specific aspects of
that cause, e.g. cleaning floors and equipment – each aspect represents a
smaller bone.
A good way to discuss and identify causes of problems to complete your diagram is
during a team brainstorming session. Focus on the ‘root causes’ where the most
aspects have been identified. As a starting place, ‘people’, ‘methods’, ‘materials’ and
‘machinery’ could be used as your four ‘root causes’.
Refer to Figure 1 overleaf.
Tip Sheet: Cause and Effect Analysis Tool 1
Figure 1 An example cause and effect diagram
3. Finding the root cause of the problem and how to solve it
A good way to get to the root of the problem is by asking lots of questions to find
out why waste is occurring, until you can identify the root cause.
For example, if you have a lot of wastes in your delivery area, ask yourself:
 There seems to be lots of old stock – is there a good system of stock
rotation?
 There seems to be lots of damaged stock – are goods stacked properly to
minimise damage?
 Stock room goods are unaccounted for – what happens to damaged goods?
 There seem to be lots of unnecessary ‘good’ items, e.g. cartridges for
redundant printers – what happens to goods that are ‘off-spec’?
 There seem to be frequent deliveries – could you buy in bulk?
 There are lots of paper and cardboard in the bins – what happens to
packaging?
 It’s warm/cold – is space heating effective/necessary or are doors left open
unnecessarily?
4. Quick wins
We now need to look at each root cause identified in your fishbone diagram and its
associated aspects in more detail so we can identify the ‘quick wins’. A simple
method for doing this is the scorecard approach (or decision matrix analysis).
1. Identify the factors that are most relevant to your business. These can
include availability of data, capital expenditure costs and achievable savings.
2. Start with the root cause with the most identified aspects. Taking each aspect
in turn assign a score (1-5) to each factor (a score of 1 represents high cost,
no data, low savings or maximum effort, and 5 represents low cost, data
available, high savings or minimal effort).
3. Calculate the overall score for each aspect.
Tip Sheet: Cause and Effect Analysis Tool 2
4. Rank the aspects in order of overall score (starting from highest score) and
target those aspects with the highest scores.
An example of this approach is outlined in Table 1.
Table 1 Example of scorecard approach
Water use area
Cleaning floors and
equipment
Blood collection
Carcass washing
Factor
3
4
4
4
3
Overall Rank
Score
18
1
1
1
5
4
3
3
3
3
4
1
16
14
2
3
5. Tips
Fishbones help teams link cause and effect.
Cause and effect charts (fishbone diagrams) are a great way to discuss and identify
causes of problems in a teamwork session. A mixed group of process operators,
engineers, managers, laboratory and technical staff discuss the causes of a particular
process problem while a skilled facilitator chairs the discussion. The fishbone diagram
is a useful record of the thinking. Changing facilitators for different problems is a
useful training technique to involve more people directly. The ideas flow thick and
fast once the session gets going.
Use problem-solving teams to develop solutions to waste problems.
By starting a team off with a cause and effect session you develop the shared
understanding that is needed to go on and develop solutions to waste problems.
More than any other technique, well run team sessions can help in identifying
improvement opportunities, creating involvement and communication and improving
understanding.
Tip Sheet: Cause and Effect Analysis Tool 3
www.wrap.org.uk/waste-prevention