Reflection on Robustness


Good results must be guaranteed and reproduced without errors. Beyond delivering flawless products consistently, a business must ensure the expected outcomes of its decisions. In other words, beyond controlling production processes, any company must precisely control the results of all its processes, especially those related to sales. 

Deming’s Legacy — Many years ago, Dr. Deming established the principles of total quality management, which are synthesized in its “14 Points for the Transformation of Management,” first presented in its book Out of the Crisis.” Dr. Deming's wisdom introduced the seed that would germinate with the transformation of how companies worldwide are managed. Nowadays, there is practically no brand with a minimum of recognition that does not embrace the total quality approach; to work right the first time.

The Reality for Small Businesses

Even though they are fundamental, "working right the first time" principles are not embraced in many medium-sized companies, much less in smaller ones, including retail businesses with several employees. The result is a substantial loss of competitiveness that is entirely avoidable.
We have come a long way, no doubt, but there is still a long way to go to generate a viable and widespread basis for competitiveness.
In any case, the Expansive Emotional Influence (EEI) methodology integrates the fundamentals of the total quality culture into its core, although simplifying it as much as possible. That makes it easier for SMEs and the retail trade to adopt a series of habits and procedures that I consider fundamental for their competitiveness.

Deming’s Legacy — Most of Deming's 14 Points are related to leadership. Because of the enormous importance of this aspect in developing an integral quality culture, we will reflect on it in a specific section (Fullness).

Process Capacity

A failure-free company can only be achieved—apart from developing strong leadership at all levels— through well-designed processes, which the employees must take ownership of and constantly improve. However, even though there is no alternative, very few SMEs take the time to involve their employees in designing the different processes that shape their operations. Of course, if there is little process design culture in SMEs, it is practically non-existent in the retail sector.
Without processes, variability is inevitable; therefore, delivering the same performance to customers every time, without failures, without variability, is impossible. That leads to certain customer dissatisfaction, cost overruns, and a loss of employee pride, which will make it impossible to work with parameters of excellence.
Unfortunately, there are many employers who still believe that they can maintain consistently high customer satisfaction and low costs without making an effort to give their employees pride in what they do; the pride that will get them fully involved in their assigned responsibilities and, consequently, get the job done "right the first time."

The Deming’s 14 Points:
1. Create constancy of purpose for improving products and services.
2. Adopt the new philosophy.
3. Cease dependence on inspection to achieve quality.
4. End the practice of awarding business on price alone; instead, minimize total cost by working with a single supplier.
5. Improve constantly and forever every process for planning, production, and service.
6. Institute training on the job.
7. Adopt and institute leadership.
8. Drive out fear.
9. Break down barriers between staff areas.
10. Eliminate slogans, exhortations, and targets for the workforce
11. Eliminate numerical quotas for the workforce and numerical goals for management.
12. Remove barriers that rob people of pride of workmanship, and eliminate the annual rating or merit system.
13. Institute a vigorous program of education and self-improvement for everyone.
14. Put everybody in the company to work accomplishing the transformation.

The Capability Index (Cp) is obtained from this formula:

𝐶𝑝 = (𝑈𝑆𝐿 − 𝐿𝑆𝐿)

USL=Upper Specification Limit LSL=Lower Specification Limit
σ=Standard deviation


What cannot be measured, cannot be improved. Applying this basic management principle, we must establish the appropriate indicators to observe and understand the processes' dynamics so that we can improve them without introducing variability in the change.
When we establish control indicators, we can observe through them the behavior of the process at a given time; this can be obtained with simple metrics, such as counting defective products in a given time. However, we can also control the capacity of that process to work within the limits specified by customers (specification limits.) Of course, in an environment of excellence where the company seeks zero error, it is necessary to control process capability.1

Robust processes

When a process is able to work within the limits demanded by customers without errors, it is a robust process; without variability. Therefore, a process with Cp=1.0 is less robust than another with Cp=1.33. Although we talk about "zero failures," this is an ideal since all processes (absolutely all) have a margin of variability. Knowing it through the capability indicator will be the first step to start reducing
it, but assuming that errors will never be zero.

The conclusion is that a company needs—in addition to a deep-rooted leadership—a control of its processes in terms of capability, so that continuous improvement consists of increasing the Capability Indicator (Cp); or, in other words, increasing its robustness.

1 The Capability Index is the formula used to measure a process’s capability.

This table shows the correlation between the Capability Index and the process outcomes that will be outside the specified limits.

Correlation Cp - DPMO
CpTotal Outside Limits
<1.0 ≥5.0%
1.0 0.3%
1.33 64 ppm
1.63 1 ppm

DPMO=Deffective Product x Million Opportunities. ppm=Deffective parts per million.