Efficient measurement studies
Q: My organization manufactures 150 different products with a range of property grams per square meter. There are 19 characteristics to be measured. We can’t use a gage repeatability and reproducibility (R&R) study on each product because it would be too time consuming. Our goal is to know the value of the R&R or have a general idea of the measurement system’s suitability. Given the number of products and characteristics, what alternative approach would you suggest to perform a minimum number of studies?
A: This is a common challenge in manufacturing. Each R&R study takes time and resources. If you conducted a study for all 150 of your products and 19 characteristics (assuming you studied them one at a time), that would result in 2,850 studies for just the initial assessment.
Continuing these studies at periodic intervals would be a major undertaking. You can apply risk-based thinking to this situation by asking: "How different are the 150 products and the 19 characteristics?" "Are they significantly different from one another, or is there only a subtle difference in form, fit and function?" "Will this difference affect the R&R result?" This is because product attributes play a role in reproducibility errors.
You can find a measurement system variability cause and effect diagram in Measurement Systems Analysis.1 In the fishbone diagram, under the bone representing the "part," there are examples of attributes that the can result in measurement system variability, such as mass, elastic deformation, elastic properties, supporting features, interrelated characteristics, cleanliness, adequate data, hidden geometry or operation definition.
Depending on your product, there may be others. These product attributes can result in significantly different R&R errors when measurements are made. At the same time, you cannot afford to do 2,850 studies from the example discussed earlier. If you can group the products into categories that consider the attributes mentioned earlier, this can reduce the total number of studies.
With 19 characteristics, you should consider these questions:
- How are these characteristics different?
- For example, do the products fall under four thicknesses, five diameters, five lengths and five angles?
- Are any of the characteristics unique?
- Will they require different equipment?
Even if they have similar characteristics, is the measurement range significantly different?
Conduct an assessment based on product type, characteristics and develop a matrix (see Table 1). From the example, group 150 products and 19 characteristics by a pre-defined criteria using product attributes. You would pick characteristics 1, 7 or 16 and a product from 1 to 50, and follow these three steps:
- Select 10 parts of the chosen product from the manufacturing process that represents the process variation.
- Select three appraisers that are representative of the appraiser population.
- Conduct three trials, and calculate the R&R.
Using risk-based thinking and conducting this type of measurement system analysis should significantly reduce your number of possible studies. There may be better ideas, but I’d suggest this approach because the question was to "have a general idea of the measurement system’s suitability."
Senior director, global quality
San Jose, CA
- Measurement Systems Analysis, fourth edition, Automotive Industry Action Group, 2010, p. 17.
A personnel or system issue?
Q: I am working with an engineering consultant, and my organization’s engineering team has to perform adequate checking and verification before it releases the deliverable product to the customer. Our quality management system’s (QMS) procedures and practices were created so that any employee could easily understand and use the requirements. We regularly gather the team for initial or refresher QMS training programs. But despite using these training sessions and raising corrective action requests, product deviations recur. What is the best way to prevent these deviations?
A: Most quality professionals are familiar with this question: "After all this training, why can’t people follow simple instructions and just do what they are supposed to do?" One method to address this is to hold people accountable, add these instances to their performance reviews, discipline them for noncompliance and replace them if necessary.
This, however, is not considered a best practice by quality and management experts. While it can be difficult for some managers to accept, W. Edwards Deming said that 85% of problems in any process are system-related and management’s responsibility, and a minority of issues are controlled by workers.1
For people to do what’s right, Deming promoted developing an intrinsic motivation in them. Social psychologist Douglas McGregor’s theories X and Y can provide managers insight into motivation.
Theory X assumes people dislike work, lack motivation and are irresponsible. But Theory Y assumes that if people have respectful management, they want to do their best and genuinely do not want to make mistakes.2
Today, Theory Y is considered a best practice. Many books on management suggest using tools such as compassionate leadership, empowerment, engagement, behavioral management or cognitive psychology. In this situation, put the burden on management, and ask yourself, "What are its responsibilities?"
Assume that people making mistakes would agree there is a problem, and they’d be happy if the mistakes went away. Perhaps deviations occur because the work is not considered interesting or important. Maybe training sessions are boring, or people are too busy to pay attention to minor details in their work.
Open a dialogue with people who are making mistakes, and let them explain what’s causing problems. If an organization’s culture does not have trust among its staff members, however, a confidential and neutrally facilitated focus group could draw out the source of the problems.
An organization’s culture is where management can make a difference. Managers must make it easier for people to follow procedures than not follow them.
That’s true, but managers also must think beyond quality system process development. They must cultivate a culture that engages and intrinsically motivates staff members: where they want to do the right thing for the organization whether it’s easy or not. The key is creating an environment in which "I have to" becomes "I want to."
Daniel Pink, author of Drive: The Surprising Truth About What Motivates Us,3 wrote that rewards and punishment have limited effects. People are motivated by autonomy, mastery and purpose.
Autonomy is the freedom to choose how to work with respect to tasks, teams, techniques or time management. In this case, perhaps the people making mistakes would like to revise relevant processes and documents to fit their preferences. To gauge the autonomy of an organization’s culture, Pink suggested performing an autonomy audit.4
Mastery can be the most influential staff motivator: The feeling of making progress in meaningful work and continuously improving at it. With regard to your deliverables, staff members must understand that these determine the organization’s success.
They also must be challenged to continuously improve the processes involved in creating your products in terms of quality, time and cost. They should be owners and masters of these processes. The QMS procedures, checks and verifications are all tools toward this end and also can be improved.
Pink’s concept of purpose suggests that people ultimately work for a cause larger than themselves, and management can help instill this feeling.Rally people around a higher cause, not just the work. Focus on what types of products you produce, their function in society and what happens if they are not produced in a timely fashion with high quality. Karen Martin, author of The Outstanding Organization, wrote that chaos must be eliminated before organizations can reach their potential.5 Chaos is a lack of clarity, focus, discipline and engagement. Promoting engagement is a key to preventing seemingly simple mistakes, and it requires an organization to emphasize the roles of connection, control and creativity.
People making the mistakes have the power. They can choose to work with you and solve the problem, or they can choose to perpetuate the current state. Your job is to be they type of leader they accept and want to let influence them. Author Manley Hopkinson wrote about different bases of power, writing that reward and coercion were the lowest levels.6
Managers should strive to reach the higher levels of influence. A culture that draws out the best in people can be subtle. Small words matter. Hopkinson recommends referring to people respectfully. Call them and think of them as people, not as bodies, workers, resources or something that can be used. Read the books on leadership I mentioned earlier, and apply management styles that make sense for your organization. It is possible for anyone to take an organization’s culture to the next level.
I focused on Deming’s 85% probability that the issues are in management’s control. There may be a reason to return to the first part of this answer: Some people might just be bad hires. These individuals will resist any attempt to build a positive, engaging culture. If they don’t improve after management has tried every reasonable step to motivate them, they are not fit to work in your organization.
Scott A. Laman
Senior manager, quality engineering
and risk management
References and note
- Michael J. Tortorella, "The Three Careers of W. Edwards Deming," Deming.org, http://tinyurl.com/threecareersofdeming.
- "Theory X and Theory Y," Mindtools.com, http://tinyurl.com/theoriesxandy.
- Daniel H. Pink, Drive: The Surprising Truth About What Motivates Us, Riverhead Books, 2011.
- Daniel H. Pink’s autonomy audit uses four questions that ask about a staff’s tasks, time and team management, and work techniques. For more information visit, www.danpink.com/audit.
- Karen Martin, The Outstanding Organization, McGraw-Hill Education, 2012.
- Manley Hopkinson, Compassionate Leadership, Piatkus, 2014.