Thanks to you, your company just saved $56,400 in variable cost and $15 Million in opportunity cost. This comes from eliminating 9 unnecessary group meetings, 12 hours of individual work and a minimum of 3 weeks of delay time to market launch.
In Steps 1 and 2, we assessed the “impact” portion of Risk Assessment (Risk = Impact x Occurrence). In today’s article, Steps 3 and 4 will cover “Occurrence” and Control Strategy.
Step 3: Assess Occurrence
Now that your QbD team has been spoiled by the efficiency of your Impact assessment, they can’t go back to the old inefficient way. In fact, the team should know the next step by now.
Occurrence is simpler. As you have delegated impact assessment to process owners as individual assignments, you can do the same here. Just ask the process owners to assess “occurrence” for their own areas.
Just make sure the scale is consistent. The best way is to set up a scale that everyone can refer to beforehand.
Below is a screenshot of the Occurrence. Process owners only rate the “CPP Occurrence” based on a 0 to 10 scale.
Step 4: Control Strategy (that is Actually Useful)
Finally, after the impact and occurrence assessments, it is ripe for a meaningful team discussion. Now is the time where group meetings make sense.
The first chart is the Relative Occurrence / Impact chart. This graph plots impact and occurrence on a 2 x 2 matrix. Why is this special?
Generic FMEA spreadsheets only show you a summarized number called the Risk Priority Number (RPN). Experts agree that this is an oversimplified number – in other words – not so helpful.
Instead of blindly using an oversimplified 1-dimensional number, you can separate the impact scores and the occurrence scores of a CQA or a CPP by using the impact-occurrence graph below.
Accordingly, Control Strategy should be different between a high-impact, low-occurrence (top left quadrant) and a low-impact, high-occurrence (bottom right quadrant). If you are using only RPN scores to judge criticality, you can not do this.
After you look at the Occurrence by Impact graph you may find the “criticality” of some process parameters may surprise you. Now is the time to discuss and calibrate with your team. Since risk ratings are subjective, you should refer back to the individual ratings to calibrate among your team members.
For a Pareto view, you can plot CQA’s and CPP’s in a Pareto chart. So the chart below may give you further guidance.
First, the CQA pareto is shown below. Quality Attributes are ranked by impact score to answer the question – How likely is the CQA to affect QTPP?.
Next, Process Parameters are ranked by impact score to answer the question – How likely is the CPP to affect QTPP?
Key Point: In a control strategy, you control X’s (CPP’s), not Y’s (CQA’s). Y’s are the result of X’s in the Design Space, Y = F(X).
In many QbD risk assessments, I’ve seen folks stopping at the CQA level — without drilling deeper into the process parameter or material attribute levels. Unfortunately these risk assessments will only tell you that “something went wrong” but without a structure to understand “why.”
Save your Team’s Time — They will Appreciate You.
Congratulations. You just gained credibility from the scientists on QbD by making a win on what could’ve turned into the most dreaded activity – risk assessment. In addition, you have a control strategy that process owners/scientists can own at the development stage.
So how did we save so much time?
- Use Templates (aMab for this article, Generic Tablets also available). Instead of beginning a Risk Assessment from scratch, you can begin with this template and modify it to your needs. This eliminates the non-value add time of “reinventing the wheel.”
- Use Lean Principles for meetings. I used specifically 2 Lean concepts for this activity. In the next article, I will reveal how these two concepts were applied to QbD Risk Assessment.
The joy is not over yet. With this system, updating Risk Assessment periodically is easy — a key behavioral requirement for keeping Risk Assessment alive and useful.
How to Get the Template:
If you already purchased the QbD Risk Assessment Software, you have this template to kickstart your QbD Risk Assessment. If your QbD project is around an Immediate Release Tablet, it is in the software as well.
So my question for you – Can you guess which 2 lean principles were used?