SIST-TP ISO/TR 22514-4:2010
Statistical methods in process management - Capability and performance - Part 4: Process capability estimates and performance measures
Statistical methods in process management - Capability and performance - Part 4: Process capability estimates and performance measures
ISO/TR 22514-4:2007 describes process capability and performance measures that are commonly used.
Méthodes statistiques dans la gestion de processus - Aptitude et performance - Partie 4: Estimations de l'aptitude de processus et mesures de performance
Statistične metode za obvladovanje procesov - Zmogljivost in delovanje - 4. del: Ocene zmogljivosti procesov in mere delovanja
Ta del ISO 22514 opisuje zmogljivost procesa in ukrepe za delovanje, ki se pogosto uporabljajo.
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Standards Content (Sample)
TECHNICAL ISO/TR
REPORT 22514-4
First edition
2007-12-01
Statistical methods in process
management — Capability and
performance —
Part 4:
Process capability estimates and
performance measures
Méthodes statistiques dans la gestion de processus — Aptitude et
performance —
Partie 4: Estimations de l'aptitude de processus et mesures de
performance
Reference number
©
ISO 2007
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2007
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2007 – All rights reserved
Contents Page
Foreword. iv
Introduction . v
1 Scope .1
2 Terms and definitions .1
2.1 Basic terms.1
2.2 Process capability, estimates and indices.5
2.3 Process performance, measures and indices .8
3 Symbols and abbreviated terms .10
3.1 Symbols .10
3.2 Abbreviated terms .12
4 Statistical measures used in process capability and performance .13
4.1 General.13
4.2 Measures of location .13
4.3 Measures of dispersion.13
4.4 Mean square error (MSE) .13
4.5 Reference limits .13
4.6 Reference interval, also known as process spread .13
4.7 Attributes .13
5 Capability.14
5.1 General.14
5.2 Process capability .15
5.3 Process location .16
5.4 Process capability indices for measured data .17
5.5 Process capability indices for measured data (non-normal) .19
5.6 Alternative method for describing and calculating process capability estimates .21
5.7 Other capability indices for measured data in other special cases .22
5.8 Assessment of proportion out-of-specification (normal distribution).23
5.9 Attributes .24
6 Performance .25
6.1 General.25
6.2 Process performance indices for measured data (normal distribution).26
6.3 Process performance indices for measured data (non-normal distribution).27
6.4 Other performance indices for measured data.28
6.5 Assessment of proportion out-of-specification (normal distribution).28
6.6 Attributes .28
Annex A (informative) Estimating standard deviations.29
Annex B (informative) Estimating capability and performance measures using Pearson curves —
Procedure and example .31
Annex C (informative) Distribution identification .39
Annex D (informative) Confidence intervals.44
Annex E (informative) Example of the output from computer software.46
Bibliography .48
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
In exceptional circumstances, when a technical committee has collected data of a different kind from that
which is normally published as an International Standard (“state of the art”, for example), it may decide by a
simple majority vote of its participating members to publish a Technical Report. A Technical Report is entirely
informative in nature and does not have to be reviewed until the data it provides are considered to be no
longer valid or useful.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO/TR 22514-4 has been prepared by Technical Committee ISO/TC 69, Applications of statistical methods,
Subcommittee SC 4, Applications of statistical methods in process management.
ISO 22514 consists of the following parts, under the general title Statistical methods in process management
— Capability and performance:
⎯ Part 1: General principles and concepts
⎯ Part 3: Machine performance studies for measured data on discrete parts
⎯ Part 4: Process capability estimates and performance measures [Technical Report]
In the future, it is planned to revise ISO 21747:2006 (Statistical methods — Process performance and
capability statistics for measured quality characteristics) as Part 2.
NOTE ISO/TR 22514-4 was initially prepared as ISO/DTR 12783. It was renumbered before publication to include it
in the ISO 22514 series.
iv © ISO 2007 – All rights reserved
Introduction
Many organizations have embarked upon a continuous improvement strategy. To comply with such a strategy,
any organization will need to evaluate the capability and performance of its key processes. The methods
described in this part of ISO 22514 are intended to assist any management in this respect. These evaluations
need to be constantly reviewed by management so that actions compatible with continuous improvement can
be taken when required.
The content of this part of ISO 22514 has been subject to large shifts of opinion during recent times and this
report attempts to reflect the current position. The most fundamental shift has been to philosophically separate
what is named in this document as capability conditions from performance conditions, the primary difference
being whether statistical stability has been obtained (capability) or not (performance). This naturally leads onto
the two sets of indices that are to be found in their relevant clauses. It has become necessary to draw a firm
distinction between these since it has been observed in industry that companies have been deceived about
their true capability position due to inappropriate indices being calculated and published.
The progression of this part of ISO 22514 is from the general condition to the specific and this approach leads
to general formulae being presented before their more usual but specific manifestations.
There exist numerous references that describe the importance of understanding the processes at work within
any organization, be it a manufacturing process or an information handling process. As organizations compete
for sales with each other, it has become increasingly apparent that it is not only the price paid for a product or
service that matters so much, but also what costs will be incurred by the purchaser from using such a product
or service. The objective for any supplier is to continually reduce variability and not to just satisfy specification.
Continual improvement leads to reductions in the costs of failure and assists in the drive for survival in an
increasingly more competitive world. There will also be savings in appraisal costs for as variation is reduced
the need to inspect product might disappear or the frequency of sampling might be reduced.
Process capability and performance evaluations are necessary to enable organizations to assess the
capability and performance of their suppliers. Those organizations will find the indices contained within this
part of ISO 22514 useful in this endeavour.
Quantifying the variation present within a process enables judgement of its suitability and ability to meet some
given requirement. The following paragraphs and clauses provide an outline of the philosophy required to be
understood to determine the capability or performance of any process.
All processes will be subject to certain inherent variability. This part of ISO 22514 does not attempt to explain
what is meant by inherent variation, why it exists, where it comes from nor how it affects a process. This part
of ISO 22514 starts from the premise that it exists and is stable.
Process owners should endeavour to understand the sources of variation in their processes. Methods such as
flowcharting the process and identifying the inputs and outputs from a process assist in identification of these
variations together with the appropriate use of cause and effect (fishbone) diagrams.
It is important for the user of this part of ISO 22514 to appreciate that variations exist that will be of a short-
term nature as well as those that will be of a long-term nature and that capability determinations using only the
short-term variation might be greatly different to those which have used the long-term variability.
When considering short-term variation, a study that uses only the shortest-term variation, sometimes known
as a machine study, might be carried out. The method required to carry out such a study will be outside the
scope of this part of ISO 22514; however, it should be noted that such
...
SLOVENSKI STANDARD
01-julij-2010
6WDWLVWLþQHPHWRGH]DREYODGRYDQMHSURFHVRY=PRJOMLYRVWLQGHORYDQMHGHO
2FHQH]PRJOMLYRVWLSURFHVRYLQPHUHGHORYDQMD
Statistical methods in process management - Capability and performance - Part 4:
Process capability estimates and performance measures
Méthodes statistiques dans la gestion de processus - Aptitude et performance - Partie 4:
Estimations de l'aptitude de processus et mesures de performance
Ta slovenski standard je istoveten z: ISO/TR 22514-4:2007
ICS:
03.120.30 8SRUDEDVWDWLVWLþQLKPHWRG Application of statistical
methods
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
TECHNICAL ISO/TR
REPORT 22514-4
First edition
2007-12-01
Statistical methods in process
management — Capability and
performance —
Part 4:
Process capability estimates and
performance measures
Méthodes statistiques dans la gestion de processus — Aptitude et
performance —
Partie 4: Estimations de l'aptitude de processus et mesures de
performance
Reference number
©
ISO 2007
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2007
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2007 – All rights reserved
Contents Page
Foreword. iv
Introduction . v
1 Scope .1
2 Terms and definitions .1
2.1 Basic terms.1
2.2 Process capability, estimates and indices.5
2.3 Process performance, measures and indices .8
3 Symbols and abbreviated terms .10
3.1 Symbols .10
3.2 Abbreviated terms .12
4 Statistical measures used in process capability and performance .13
4.1 General.13
4.2 Measures of location .13
4.3 Measures of dispersion.13
4.4 Mean square error (MSE) .13
4.5 Reference limits .13
4.6 Reference interval, also known as process spread .13
4.7 Attributes .13
5 Capability.14
5.1 General.14
5.2 Process capability .15
5.3 Process location .16
5.4 Process capability indices for measured data .17
5.5 Process capability indices for measured data (non-normal) .19
5.6 Alternative method for describing and calculating process capability estimates .21
5.7 Other capability indices for measured data in other special cases .22
5.8 Assessment of proportion out-of-specification (normal distribution).23
5.9 Attributes .24
6 Performance .25
6.1 General.25
6.2 Process performance indices for measured data (normal distribution).26
6.3 Process performance indices for measured data (non-normal distribution).27
6.4 Other performance indices for measured data.28
6.5 Assessment of proportion out-of-specification (normal distribution).28
6.6 Attributes .28
Annex A (informative) Estimating standard deviations.29
Annex B (informative) Estimating capability and performance measures using Pearson curves —
Procedure and example .31
Annex C (informative) Distribution identification .39
Annex D (informative) Confidence intervals.44
Annex E (informative) Example of the output from computer software.46
Bibliography .48
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
In exceptional circumstances, when a technical committee has collected data of a different kind from that
which is normally published as an International Standard (“state of the art”, for example), it may decide by a
simple majority vote of its participating members to publish a Technical Report. A Technical Report is entirely
informative in nature and does not have to be reviewed until the data it provides are considered to be no
longer valid or useful.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO/TR 22514-4 has been prepared by Technical Committee ISO/TC 69, Applications of statistical methods,
Subcommittee SC 4, Applications of statistical methods in process management.
ISO 22514 consists of the following parts, under the general title Statistical methods in process management
— Capability and performance:
⎯ Part 1: General principles and concepts
⎯ Part 3: Machine performance studies for measured data on discrete parts
⎯ Part 4: Process capability estimates and performance measures [Technical Report]
In the future, it is planned to revise ISO 21747:2006 (Statistical methods — Process performance and
capability statistics for measured quality characteristics) as Part 2.
NOTE ISO/TR 22514-4 was initially prepared as ISO/DTR 12783. It was renumbered before publication to include it
in the ISO 22514 series.
iv © ISO 2007 – All rights reserved
Introduction
Many organizations have embarked upon a continuous improvement strategy. To comply with such a strategy,
any organization will need to evaluate the capability and performance of its key processes. The methods
described in this part of ISO 22514 are intended to assist any management in this respect. These evaluations
need to be constantly reviewed by management so that actions compatible with continuous improvement can
be taken when required.
The content of this part of ISO 22514 has been subject to large shifts of opinion during recent times and this
report attempts to reflect the current position. The most fundamental shift has been to philosophically separate
what is named in this document as capability conditions from performance conditions, the primary difference
being whether statistical stability has been obtained (capability) or not (performance). This naturally leads onto
the two sets of indices that are to be found in their relevant clauses. It has become necessary to draw a firm
distinction between these since it has been observed in industry that companies have been deceived about
their true capability position due to inappropriate indices being calculated and published.
The progression of this part of ISO 22514 is from the general condition to the specific and this approach leads
to general formulae being presented before their more usual but specific manifestations.
There exist numerous references that describe the importance of understanding the processes at work within
any organization, be it a manufacturing process or an information handling process. As organizations compete
for sales with each other, it has become increasingly apparent that it is not only the price paid for a product or
service that matters so much, but also what costs will be incurred by the purchaser from using such a product
or service. The objective for any supplier is to continually reduce variability and not to just satisfy specification.
Continual improvement leads to reductions in the costs of failure and assists in the drive for survival in an
increasingly more competitive world. There will also be savings in appraisal costs for as variation is reduced
the need to inspect product might disappear or the frequency of sampling might be reduced.
Process capability and performance evaluations are necessary to enable organizations to assess the
capability and performance of their suppliers. Those organizations will find the indices contained within this
part of ISO 22514 useful in this endeavour.
Quantifying the variation present within a process enables judgement of its suitability and ability to meet some
given requirement. The following paragraphs and clauses provide an outline of the philosophy required to be
understood to determine the capability or performance of any process.
All processes will be subject to certain inherent variability. This part of ISO 22514 does not attempt to explain
what is meant by inherent variation, why it exists, where
...
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