Reducing Common Cause Variation - Pharmaceutical Technology

Latest Issue
PharmTech

Latest Issue
PharmTech Europe

Reducing Common Cause Variation
Where is the variability coming from and what have we done to minimize it?
Feb 2, 2012
By: Lynn D. Torbeck
Pharmaceutical Technology
 Volume 36, Issue 2, pp. 32
12
Next »


PHOTODISC/GETTY IMAGES
Textbooks and journal articles treat common cause variation as if it is an inevitable fact of nature and beyond our control: "In any production process, regardless of how well-designed or carefully maintained it is, a certain amount of inherent or natural variability will always exist. This natural variability or 'background noise' is the cumulative effect of many small, essentially unavoidable causes" [Emphasis added] (1). This attitude cuts off thoughts of trying to reduce variation. But, with some reflection, there are several ideas and techniques that can begin to help reduce common cause variation.

Work to hit the target


Lynn D. Torbeck
Aiming for and hitting the target, whether it is x, y or z, seems a simple idea, but it could be argued that it is everybody's responsibility to know what the target is and to do everything possible to hit that target every time. One person achieving the target infrequently doesn't help. But 400 people hitting targets a dozen times a day can have a dramatic effect on reducing variability. The target could be something as simple as setting the temperature on a dryer or as complex as a management objective. Keep in mind that a specification range is not a playground for manufacturing.

This mindset also can influence how specifications criteria are written. It is common to write the criteria as "(Low, High)." I suggest that criteria are better written as, "Target (Low, High)." The first thing the operator sees is the target value; people generally try to achieve the first thing they see. Second, the low and high criteria limits are given, which eliminates the need to mentally calculate those limits (e.g., if Target ±Δ, was used instead). The limits need not be symmetrical with the target value.

Flexible consistency

The terms sound contradictory but do contain logic. Many activities are at the liberty of the operator or analyst and, as such, are subject to considerable leeway in how they are performed. In these situations, particularly in the analytical laboratory, one strives to get everybody on the team to do exactly the same thing, the same way, every time. If then, at some point in the future someone proposes a new or better way to perform the task, the whole team changes to follow the new process. This group consistency can have a substantial impact on variation within a department. Notably, creativity of the individual is not stifled, but rather channeled to find better ways to perform a task.

Operational definitions

"An operational definition describes what something is and how it is measured" (2). For example, "sample the batch" could mean: "Using the 72 in. thief, open the port on the right side labeled P8, and take a sample from the top two inches, a sample from the middle, and a sample two inches from the bottom. Composite the three samples into a clean glass jar with a lid, and label with the date, time, name, product, lot and vat number." Operational definitions reduce variation by promoting consistency. Standard operating procedures are a form of operational definitions.

12
Next »

ADVERTISEMENT

post a comment
Please complete the form below to post your comment.
Bold = Required
Email Address Your email address will NOT be published.
Display Name appears with your comment
City
State
Country
Remember me: YesNo
Comment read our privacy policy
Note: does not support HTML
All comments submitted are subject to review, and may be delayed before posting. We reserve the right not to post comments.
About the Author

Lynn D. Torbeck

international consultant and trainer
http://www.torbeck.org

Lynn D. Torbeck is an international consultant and trainer specializing in applied statistics and experimental design for pharmaceutical, biopharmaceutical, and medical device research and development, validation, quality control/assurance, and production, 2000 Dempster Plaza, Evanston, IL 60202, tel. 847.424.1314. Articles by Lynn D. Torbeck

LCGC E-mail Newsletters

Subscribe: Click to learn more about the newsletter
| Weekly
| Monthly
|Monthly
| Weekly

Survey
Do you believe the pharma manufacturing industry is becoming more transparent overall?
Yes
No
It's the same as always has been
Yes
43%
No
29%
It's the same as always has been
29%
View Results
Jim MillerOutsourcing OutlookJim Miller Channeling Steve Jobs
Patricia Van ArnumIngredients InsiderPatricia Van ArnumSeeking Chemocatalytic and Biocatalytic Solutions
Nathan JessopIndustry InsiderNathan Jessop Taxing Times for French Pharma
Lynn D. TorbeckStatistical Solutions Lynn D. TorbeckRepresentative Sampling
Parallel Trade Fuels UK Drug Shortages
Single-use Systems Proliferate
Report on Recent and Upcoming Single-Use Meetings
ICH Q11 Reaches Harmonization, Implementation is Next
Digital Signatures Growing as a Result of Part 11

FindPharma Custom Search
Featured Jobs

More Jobs

Source: Pharmaceutical Technology, 2/2/2012
Click here