SETTING ACCEPTANCE CRITERIA FOR VALIDATION
What Are Acceptance Criteria?
 Specified indicators or measures, employed
in assessing the ability of a component, structure, or system to perform its intended function.
What Are Acceptance Criteria?
 In terms of validation, acceptance criteria establish that your validation will meet it’s intended purpose.
What Validation Acceptance Criteria is Not
 Not a measure of product quality!!!
 No simply a checkbox on the road to product launch.
The Concept of Variance
(and why it is important)
 Variance is the natural tendency of a system not to end up in the same place every time (my definition).
 In other words, it is what happens when I test the same sample 100 times and get 100 different answers.
The Concept of Variance
 Sources of variance
 Equipment
 Location
 People
 Measurement system
 Materials
 Understanding the variance in your system is KEY to setting appropriate validation acceptance criteria.
The Concept of Variance
 In order to understand the variance in your system, you must completely (or to the best o your ability) characterize your process or test method.
The Concept of Variance
 Normal distribution
 Results are spread evenly around a target.
 There is no “bias” in the system
The Concept of Variance
 In validation, your variance should be “normal”.
 If you find that there is a “bias” in the data generated out of characterization, the system might need a bit of adjustment.  Non‐normal variance can be accounted for in validation.
Setting Acceptance Criteria
 Now that we have an understanding of variance…
 And we have characterized the variance inherent in our system…
 We can begin to set acceptance criteria for validation.
Setting Acceptance Criteria
 There are many methods of setting acceptance criteria for validation.
 I am going to focus on one in particular
 This is using Capability Indices (process capability) as a measure.
Process Capability
 Ok.. Now that we know how to measure variance, how do we use it in validation?
 How do we know if the variance in our process or test method is low enough to give us good product or tell us reliable test results?
 This is where Process Capability comes in.
Process Capability
 Using the concept of capability, we are able to set acceptance criteria for our validation to ensure that our test method can “see” the variation it needs to or our process can produce product in a reliable manor.
Process Capability
 Process Potential (CP)
 Measure that compares Allowable Process Spread with Actual Process Spread.
 USL and LSL are the upper and lower specifications for the product
 6 SD (6 sigma) gives you 99.73% degree of compliance
 + 3.0 SD on either side of the mean
 The larger the Cp, the greater the potential of the process to produce product within spec. limits
Process Capability
 Cp gives us a measure of how “good” my window is.
Process Capability
 A general industry standard is that at a minimum:
 Cp = 1 for in process testing or processes
 Cp > 1.33 for final release
 So how do you use this in practical manor to set acceptance criteria for validation??
Using Process Capability
 If:
 Then:
 This is the maximum SD your process or test method can tolerate. Just plug in what Cp you need.
Using Process Capability
 When you run your validation, if the variation (SD) is less than or equal to what will give an acceptable Cp, you pass.
 If not…
Using Process Capability (a few more points)
 One Sided Specifications
 No spec range (exactly)
 Use one or the other depending if you have a lower spec or an upper one.
Using Process Capability (a few more points)
 Cp does not account for “Off‐Aim” Performance
 In this case we use an index called Cpk
 k is shift factor that measures how “off” we are.
Using Process Capability (a few more points)
,
 If Cp = Cpk, the process is centered..
 Even if the process is not centered, if Cpk
acceptable, it is “OK”.  You would strive for a centered process.
In Summary
 Using process capability as an acceptance specification is an easy way to determine if you test method or process is acceptable for use.
 If you meet your predetermined process capability acceptance specification, you have assurance your test method or process will meet your needs.
Thank You For Your Attention
 My Contact Information:
 Alan Golden
 Senior Quality Professional
 Abbott Molecular
 Alan.golden@abbott.com
 224‐361‐7159