But Why?

But why? Why is nothing working right? Root cause analysis is the headline and Y=f(X) is the linear equation. And the question is often Why?

“A relentless barrage of “why’s” is the best way to prepare your mind to pierce the clouded veil of thinking caused by the status quo. Use it often.” – Shigeo Shingo When facing a problem, before jumping into solving the issue, it is critical to begin with assessing why the problem occurred. This is referred to as conducting a root cause analysis. The key is to identify the cause that leads to the effect, the failiure. In other terms, we want to identify the independent variables, the x's, that drive the dependent variable, the y. Y=f(X1, X2, X3...). There are a handful of common tools to help an individual or team assess the causes of a problem. These include 5 Whys, Cause & Effect Diagram, 6M, FMEA, Fault Tree Analysis and more. The more data that is available in evaluating a problem, the more effective the root cause analysis will be. This blog today will describe 5 Whys, my favorite tool. I like to begin with 5 Why's when training an organization as this is a simple tool that can be widely applied. It is acceptable to use in assessing smaller scoped issues where there are fewer channels to follow. The approach is simple. This is an iterative approach in identifying the cause of a problem. The process? Simply ask Why 5 times or until you have come to the right level of cause. When assessing the cause(s) of a problem we start with a good problem statement, something we will write about in a separate blog. But as we look at examples of applying 5 Whys, I will try to model some good problem statements. Let's start with an example. An example problem statement: Last month, our product A shipped late to the customer 38% of the time causing customer dissatisfaction and costing the organization $8000 in late arrival fees. Why?: We've never been able to get product A out the door on time. Why?: We're always late to our production schedule Why?: Our raw material arrives late so we can't start production on time Why?: Our raw material supplier is using a 2nd rate logistics partner Why?: Our raw material supplier does not want to spend money on shipping Is this far enough? I think so. From here we can brainstorm potential corrective actions. For example, perhaps we can require that our supplier uses our freight forwarder instead, that we take the logistics cost and negotiate a reduced overall price of this raw material. That potential increase in our logistics cost may be less than the late arrival fees we are paying and certainly may be worth increasing customer satisfaction which could result in more business. Let's try another example. An example problem statement: In the past quarter, we have seen an increase in scrap cost of our flagship product A resulting in an increased product cost of 6% due to additional labor and material. Why?: We were having issues with the tooling wearing down, so we updated the tooling 3 months ago Why?: The new tooling seems to have more issues than the worn down tooling Why?: We have a new tooling supplier that doesn't seem to understand our tooling needs Why?: We did not properly qualify the new supplier tools in our production line before going live with the new tooling Why?: We do not have a good New Tooling Introduction program at our plant Is this far enough? I think so. From here we can start developing a new tooling introduction prorgram to qualify the tooling on the production line and qualify parts coming off of that line to the specification. The cost of time and resources to perform the qualification of new tools will certainly be less than the cost of scrap over time. 5 Whys is not always the right fit. One option is to run 5 Whys a few times to follow different channels. Looking at this second example, perhaps the flagship product A has seen an (why) increase in volume requiring an (why) increase in labor resources and here there could be an (why) element of human error because (why) the production process is complex. Okay, so we got to 4 Whys on the second run. The corrective actioni could be poka yoking a production process, creating jigs and more, to reduce the risk for human error. And another option is to employ another root cause analysis tool.