ASTM E2281-03e1

Standard Practice for Process and Measurement Capability Indices

SCOPE
1.1 This practice provides guidance for the use of capability indices for evaluating process capability and performance. Process capability indices compare the variability of a process quality measure against product specifications or tolerances and assume the process is in a state of statistical control. Process performance indices are useful in situations when the process is not in a state of statistical control.

General Information

• Status: Historical
• Publication Date: 09-Jun-2003
• ICS: 25.040.40 - Industrial process measurement and control
• Technical Committee: E11 - Quality and Statistics
• Drafting Committee: E11.30 - Statistical Quality Control

Relations

• Replaces: ASTM E2281-03 - Standard Practice for Process and Measurement Capability Indices
• Effective Date: 10-Jun-2003
• Replaced By: ASTM E2281-08 - Standard Practice for Process and Measurement Capability Indices
• Effective Date: 01-Apr-2008
• Referred By: ASTM B945-21 - Standard Practice for Aluminum Alloy Extrusions Press Cooled from an Elevated Temperature Shaping Process for Production of T1, T2, T5 and T10-Type Tempers
• Effective Date: 10-Jun-2003
• Referred By: ASTM E2656-16 - Standard Practice for Real-time Release Testing of Pharmaceutical Water for the Total Organic Carbon Attribute
• Effective Date: 10-Jun-2003
• Referred By: ASTM B947-14(2020)e1 - Standard Practice for Hot Rolling Mill Solution Heat Treatment for Aluminum Alloy Plate
• Effective Date: 10-Jun-2003
• Referred By: ASTM E2475-10(2016) - Standard Guide for Process Understanding Related to Pharmaceutical Manufacture and Control
• Effective Date: 10-Jun-2003
• Referred By: ASTM E456-13a(2022) - Standard Terminology Relating to Quality and Statistics
• Effective Date: 10-Jun-2003
• Referred By: ASTM E2587-16(2021)e1 - Standard Practice for Use of Control Charts in Statistical Process Control
• Effective Date: 10-Jun-2003
• Referred By: ASTM E3239-21 - Standard Guide for Using Statistical Process Control Principles for Routine Dosimetry in Radiation Processing
• Effective Date: 10-Jun-2003
• Referred By: ASTM B807/B807M-20 - Standard Practice for Extrusion Press Solution Heat Treatment for Aluminum Alloys
• Effective Date: 10-Jun-2003
• Referred By: ASTM E3106-22 - Standard Guide for Science-Based and Risk-Based Cleaning Process Development and Validation
• Effective Date: 10-Jun-2003
• Referred By: ASTM F2554-22 - Standard Practice for Measurement of Positional Accuracy of Computer-Assisted Surgical Systems
• Effective Date: 10-Jun-2003

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
e1
Designation: E 2281 – 03
Standard Practice for
1
Process and Measurement Capability Indices
This standard is issued under the fixed designation E2281; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1
e NOTE—Section 3 was corrected editorially in May 2007.
1. Scope 3.1.3 lower process capability index, C , n—index de-
pkl
scribingprocesscapabilityinrelationtothelowerspecification
1.1 Thispracticeprovidesguidancefortheuseofcapability
limit.
indices for evaluating process capability and performance.
3.1.4 lower process performance index, P , n—index de-
Process capability indices compare the variability of a process pkl
scribing process performance in relation to the lower specifi-
quality measure against product specifications or tolerances
cation limit.
and assume the process is in a state of statistical control.
3.1.5 minimum process capability index, C , n—smaller of
pk
Process performance indices are useful in situations when the
the upper process capability index and the lower process
process is not in a state of statistical control.
capability index.
2. Referenced Documents 3.1.6 minimum process performance index, P , n—smaller
pk
2
of the upper process performance index and the lower process
2.1 ASTM Standards:
performance index.
E456 Terminology Relating to Quality and Statistics
3.1.7 process capability, PC, n—statistical estimate of the
2.2 ISO Standard:
outcome of a characteristic from a process that has been
ISO 3534-2 Statistics—Vocabulary and Symbols-Statistical
3
demonstrated to be in a state of statistical control.
Quality Control
3.1.8 process capability index, C , n—an index describing
p
2.3 Other Document:
process capability in relation to specified tolerance.
MNL 7 Manual on Presentation of Data and Control Chart
4
3.1.9 process performance, PP, n—statistical measure of
Analysis
the outcome of a characteristic from a process that may not
3. Terminology
have been demonstrated to be in a state of statistical control.
3.1.10 process performance index, P , n—index describing
3.1 Definitions: Unless otherwise noted, all statistical terms
p
process performance in relation to specified tolerance.
are defined in Terminology E456.
3.1.11 range, R, n—thelargestobservationminusthesmall-
3.1.1 average standard deviation, s¯, n—arithmetic average
est observation in a set of values or observations.
of sample standard deviations.
3.1.12 short term standard deviation, s , n—the inherent
3.1.2 long term standard deviation, s , n—sample stan-
ST
LT
variation present when a process is operating in a state of
dard deviation of all individual (observed) values taken over a
statistical control, expressed in terms of standard deviation.
long period of time.
3.1.12.1 Discussion—This may also be stated as the inher-
3.1.2.1 Discussion—A long period of time may be defined
ent process variation.
as shifts, weeks, or months, etc.
3.1.13 special cause, n—source of intermittent variation in
a process. ISO 3534-2
1
3.1.13.1 Discussion—Sometimes“specialcause”istakento
ThispracticeisunderthejurisdictionofASTMCommitteeE11onQualityand
Statistics and is the direct responsibility of Subcommittee E11.30 on DataAnalysis. besynonymouswith“assignablecause.”Howeveradistinction
Current edition approved June 10, 2003. Published July 2003.
should be recognized.Aspecial cause is assignable only when
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
it is specifically identified. Also a common cause may be
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
assignable.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
3.1.13.2 Discussion—A special cause arises because of
3
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specific circumstances which are not always present.As such,
Floor, New York, NY 10036.
4 in a process subject to special causes, the magnitude of the
Available from ASTM Headquarters, 100 Barr Harbor Drive, W. Consho-
hocken, PA 19428. variation from time to time is unpredictable.
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e1
E2281–03
3.1.14 stable process, n—process in a state of statistical manner in which these measures are calculated defines the
control; process condition when all special causes of variation different types of capability indices and their use.Two process
have been removed. ISO 3534-2
capability indices are defined in 5.2 and 5.3. In practice, these
3.
...