Kaoru Ishikawa was a Japanese professor who championed quality improvement. He is credited with the formation of quality circles, groups of workers & supervisors who work together to improve their operations.
We remember Kaoru Ishikawa for his namesake Ishikawa Diagram, more popularly known as the fishbone diagram, a tool quality circles would use to identify root causes of problems.
Via the fishbone diagram, the quality circle spells out a problem which at the onset is more of a symptom, issue, or disruption. The problem takes up the position as head of the fishbone in which a facilitator asks quality circle participants to share what they think what’s causing it. For example, if the problem is not meeting a production target, the group may cite possible causes like:
- Frequent changes in schedules
- Poorly maintained machines
- Not enough people
- Late deliveries of raw & packaging materials
- Lack of pallets
The facilitator draws a fishbone showing these causes:
‘Not meeting the production target’ makes up the ‘spine & head’ of the fishbone diagram. The causes a quality circle would bring up comprise the fishbone’s ‘primary ribs’ which connect to the problem’s spine.
The facilitator would then ask quality circle participants what they think are the causes leading to each of the primary ribs. These causes would make up the ‘secondary’ ribs of the fishbone diagram:
The secondary ribs would not only be causes for the primary ones but also would be factors for the main problem: not meeting the production target.
We don’t stop there. The facilitator would ask quality circle participants what they think are the causes for the secondary ribs. Thus, our fishbone diagram with 3rd-tier causes may look like this:
Once again, these 3rd-tier causes are not only factors behind the secondary & primary branches but also are suspect as reasons for the problem of not meeting the production target.
Note that, in this example, there are several causes that resemble supply chain issues:
- unavailable spare parts
- delayed arrival of imports
- rush customer orders
- vendors asking for payments of unpaid purchases
- many empty pallets not returned from warehouse
And we note causes that seem to involve departments or disciplines the quality circle may not belong to or have any direct scope in:
- no formal training program (human resources)
- few qualified applicants to hire (human resources)
- not enough skilled mechanics (human resources)
- poor sales & operations (S&OP) planning (sales, finance, marketing)
- limited cash flow (finance)
Quality circles had been the stereotypes for manufacturing work teams, consisting typically of rank & file workers, operators, & supervisors. Hence, a downside of quality circles is that the root causes participants may identify could lie beyond their workplace borders. Cynical observers may get the impression that quality circles are finger-pointing their failures to other functions of the enterprise.
Quality circles have faded in popularity and some of us may even label them as a bygone symbol from the 1980s quality movement. This does not mean we should chuck Ishikawa’s fishbone diagram because quality circles are no longer hip. Instead, we should recognise that there is potential in using it as an effective means to solving problems, especially supply chain ones.
As we’ve become familiar with the interconnections of supply chain operations, we’ve been realising that some problems we encounter have root causes linked either to other functions or to our relationships with vendors and customers.
Ishikawa’s fishbone diagram encourages us to identify causes to symptomatic problems, whether or not those causes originate from where we work or from shortcomings in our operating relationships with other functions or links in the supply chain.
Many enterprise quality improvement training sessions include exercises in drawing Ishikawa’s fishbone diagrams. But hardly do we see executives, managers, and rank & file staff using the fishbone diagram in meetings or crisis management sessions. Many of us have relegated the fishbone diagram more as an organisational development or teambuilding training exercise than as a real tool for solving problems or improving productivity.
We can exploit Ishikawa’s fishbone diagram if we realise it is a useful tool which any group or individual of any discipline can use. And please note the following six (6) insights we can glean from using Ishikawa’s fishbone methodology.
First, we don’t need to be in a group to use the fishbone diagram. Individual problem-solvers can use the fishbone diagram by themselves. We can make our own fishbone diagrams in seeking causes for problems we opted to study and solve. If we need help, we can research or interview people of different backgrounds to help build the fishbone and validate the ‘branches.’
Second, if we do work as a group, the members don’t necessarily need to be from a single department or function. Especially for supply chains, we should enrol people from as many disciplines as possible or at least from those areas that are upfront relevant to the problem. If we identify causes which our group would have no members to provide details on, then we should invite them.
And if or when we do form problem-solving teams, we should make sure that all members do participate. A team leader is at least a facilitator and as much as possible should not be seen as a superior (even if they may be our bosses). When it comes to team rapport in drawing the fishbone diagram, team leaders best serve as moderators or facilitators, and nothing more.
We also should not categorise anyone we invite as a resource person instead of as a participant. Doing so makes it look like we treat invitees as inferior non-members, meant to only contribute when we ask them to. By experience, resource people won’t volunteer more information than what we ask.
Third, in workplace settings, it would be nice if higher-level executives show support to inter-disciplinary problem-solving teams drawing fishbone diagrams, but if they don’t (and more often they really don’t), we should not stop ourselves from forming problem-solving teams anyway. The beauty of Ishikawa’s fishbone diagram is that it relies on the experiences and expertise of participants contributing to it, not on executives who are typically distant and not as empathetic.
Fourth, Ishikawa’s fishbone diagram is a tool to identify root causes. It is a means toward solving problems. It is not meant to bring about outright solutions. Any individual or team should be aware that solving problems is a methodical process in which Ishikawa’s fishbone diagram is just one of several innovative tools we use to look for causes.
Fishbone diagrams don’t solve problems; we do.
Fifth, as the fishbone diagram lays out all the possible causes to our problem, selecting which one we prioritise to address is an exercise in data gathering, analysis, and evaluation. We should not just outright choose a cause to solve. We should do our homework and study the root causes laid out on the fishbone before we determine which one we address as the problem to solve.
Sixth, fishbone diagrams aren’t fads. Just like wrenches & screwdrivers, it is a tool that does not become obsolete. Tools are useful and beneficial only when we use them (and know how to use them).
The aim of the fishbone diagram is to make known all possible (if not probable) causes to a problem, which at the start is more of a symptom, issue, or disruption. From the fishbone branches, we narrow down and decide which one or few root causes shall deserve our wholehearted attention.
We can use Ishikawa’s fishbone diagram either by ourselves as individuals or via groups we form. Some top management support would be helpful, but we can still form teams and use the fishbone informally by ourselves. Everyone in a group should participate in drawing the fishbone diagram and we should treat co-members of our problem-solving group as equals by welcoming whatever they contribute.
Kaoru Ishikawa advocated for quality improvement in our operations. He taught us the importance of quality circles and gave us the fishbone diagram. Thanks to him, we have a useful and effective tool from which we not only can identify root causes to problems but in the long run, continuously improve our operations and our businesses.
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