QC Rules

 

Content

Introduction

Add a New QC Rule

 

QC Evaluation Rules and Control Limits

Reference QC Evaluation Rules on a QCMethod

 

Introduction

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QC Rules let you define the statistical process control method to apply when evaluating QC Batches. Define the method using Western Electric Company (WECO) Rules and the Westgard Multi-Rules Procedure.

A QC Rule is a directive used during the evaluation of the QC Samples of a QCBatch. These directives can determine when a QCBatch is trending out of control and show when an individual datapoint is outside of a limit range or exhibits a trending tendency.

When the QC Rule defined here is included on a QC Method, these rules are applied to the QC Batch Sample data.

 

Add a New QC Rule

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To create a new QC Rule navigate to the AQC → QC Rules tramstop. The QC Evaluation Rules List page displays.

Click "Add" to add a new rule or select an existing rule and click "Edit" to make changes.

Identify the Rule

Identify, and provide additional information about the rule.

Field Description
Evaluation Rule Id Identifier of the QC Rule.
Description Textual description.
Notes Additional information about the QC Method.

Define the Rules

 After saving, the Rule detail displays (shown below with rules already added).

To define Rules and their criteria, click "Add".

The Add/Edit QC Rule Item dialog lets you add or edit a rule:

FieldDescription
Rule The dropdown contains available QC Evaluation Rules. When you select one, the Parameters relevant to the Rule are displayed below it. Enter values according to the information in QC Evaluation Rules and Control Limits.
Limit Name

SD Multiplier

 "Limit Name" is the name of the Control Limit.

Control Limits define the number of standard deviations ("SD Multiplier") from the target. These are available for selection:

Control Limit SD Multiplier
Notification1
Warning2
Alarm3

You can also define your own Control Limit by choosing "Other", then entering a "Name" and "SD Multiplier".

When you choose one, the corresponding number of standard deviations is displayed in the "SD Multiplier" field (see QC Evaluation Rules and Control Limits).

Alternatively, you can select "Other", enter a Limit Name, then enter the desired number of standard deviations.

LabelWhen you select a Rule, this shows the (editable) name of the Rule.
DescriptionWhen you select a Rule, this shows the (editable) description of the Rule.

 

QC Evaluation Rules and Control Limits

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QC Evaluation Rules are based on the Western Electric Company (WECO) Rules and the Westgard Multi-Rules Procedure.

Evaluation Rule

Example
Parameter

The rule fails if...

N consecutive points outside same side of limitN=3 3 consecutive points are outside of the same side (+/-) of the Control Limit.
K of N consecutive points outside same side of limitK=3

N=5

 3 of 5 consecutive points are outside of the same side (+/-) of the Control Limit.
N consecutive points within +/- of limitN=5 5 consecutive points are within "+/-" of the Control Limit.
N consecutive points outside either side of limitN=3 3 consecutive points are outside of either side (+/-) of the Control Limit.
Difference between consecutive points greater than X times sdX=3The difference between the consecutive points is greater than the value of 3 times the standard deviation.
N consecutive points on same side of targetN=44 consecutive points are on the same side (+/-) of the target (center line/mean).
N consecutive points alternating up and downN=66 consecutive points are placed in an alternating pattern up and down.
N consecutive points in a decreasing trendN=44 consecutive points show a decreasing trend.
N consecutive points in an increasing trendN=44 consecutive points show an increasing trend.

 

 

Reference QC Evaluation Rules on a QC Method

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Once defined here you can associate these rules with a QC Method. As new QC Batches are created (using the QC Method) these Rules are applied to the QC Batch. See QC Methods → Evaluation Rule for more information.