Featured Video
This Week in Quality Digest Live
Lean Features
Ryan E. Day
Star Rapid partners with tool manufacturer Gühring to increase speed and improve quality
Jim Benson
You can’t set up an operational imperative and have someone else meaningfully improve it
Bruce Hamilton
Who is accountable?
Bruce Hamilton
When visual devices are the sole standard for visual controls, managers learn little about the gemba

More Features

Lean News
SQCpack and GAGEpack offer a comprehensive approach to improving product quality and consistency
Management's role in improving work climate and culture
Customized visual dashboards by Visual Workplace help measure performance
Helps manufacturers by focusing on problems and problem resolution in real time
Ask questions, exchange ideas and best practices, share product tips, discuss challenges in quality improvement initiatives
It’s time that healthcare began to learn a long-term strategic approach to transformation
Combines 3D scanner, touch probe, and software to reduce production times by 30%

More News

Harish Jose


Process Validation, Part 1

Ship of Theseus

Published: Tuesday, July 11, 2017 - 12:02

There is a great Greek paradox/puzzle called the Ship of Theseus. There are multiple versions and derivations to it. My favorite version is as follows (highly watered down).

Theseus bought a new ship. Each day he replaced one part of the ship. Plank by plank, sail by sail, and oar by oar. Finally, no part of the original ship remained. Now the paradox is this: Is the ship the same as the original ship now that every part has been replaced? This is a great thought experiment about identity and understanding of self. If we go one step further and build a new ship with all the parts that were replaced from the original ship, is the new ship the same as the original ship?


When I read about this great paradox, my mind started thinking about process validation. We get a new piece of equipment, say a pouch sealer, and during the course of multiple years, many of the parts get worn down and replaced. Is the sealer the same as the original sealer? Is the original validation still valid?

This is where two main aspects of the process validation are important:
1. Maintaining the validated state
2. Revalidation criteria

Maintaining the validation state includes proper monitoring of the process, once it is qualified, to ensure that it is in a state of control. For example, for a sealer validation, we might perform seal-strength testing and visual inspection based on a frequency and defined criteria. Any adverse results shall be reviewed and rectified.

The revalidation criteria can be based on predetermined criteria as well. Some examples are:
• Major parts of the equipment replaced
• Equipment relocated to a new facility
• Equipment not in use for more than a year
• Significant changes to the process, such as raw material change
• Negative trends in quality

Both maintaining the validated state and revalidation requirements must be part of a process validation protocol. In tomorrow’s column we’ll look at the problem of induction.


About The Author

Harish Jose’s picture

Harish Jose

Harish Jose has more than seven years experience in the medical device field. He is a graduate of the University of Missouri-Rolla (U.S.), where he obtained a master’s degree in manufacturing engineering and published two articles. Harish is an ASQ member with multiple ASQ certifications, including Quality Engineer, Six Sigma Black Belt, and Reliability Engineer. He is a subject matter expert in lean, data science, database programming, and industrial experiments. Harish publishes frequently on his blog harishnotebook. He can be reached on LinkedIn.


Validated State Important Concept

The concept of a validated state is not only important for validation, but it also helps one understand the difference between corrective action and improvement. A corrective action brings the process back to the valdiated state. An improvement moves the process beyond the valdiated state.