ISO/TR 7250-4
(Main)Basic human body measurements for technological design — Part 4: Expected performance of skilled anthropometrists
Basic human body measurements for technological design — Part 4: Expected performance of skilled anthropometrists
This part of ISO 7250 describes knowledge and skills required for experienced anthropometrist who serves as a measurer in anthropometric surveys or a planner of an anthropometric survey. This part of ISO 7250 also describes methods to quantify the skill of anthropometrists and to report their performance. Information on the quality control of anthropometric data is mentioned in several different standards. Measurer training by persons experienced in anthropometry is required (ISO 15535). Scan-derived measurements are evaluated using the measurements taken by an anthropometrist with several year’s experience in the methods of ISO 7250-1 as the true values (ISO 20685-1). However, expected performance of an experienced anthropometrist is not clear. This part of ISO 7250 is not a textbook or manual for anthropometry but may be useful for those who plan and conduct anthropometric surveys as well as designers and technologists who utilize anthropometric data. Methods described in this document may also be applicable to measurements other than those described in ISO 7250-1.
Définitions des mesures de base du corps humain pour la conception technologique — Partie 4: Performances attendues des anthropométristes qualifiés
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ISO /DTR 7250-4:####(X)
ISO /TC 159/SC 3/WG 1
Date: 2023-04-21
Secretariat: JISC
Date: 2023-07-04
Basic human body measurements for technological design —
Part 4:
Expected performance of skilled anthropometrists
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ISO /DTR 7250-4:####(X:(E)
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this
publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical,
including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can
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Phone: + 41 22 749 01 11
EmailE-mail: copyright@iso.org
Website: www.iso.orgwww.iso.org
Published in Switzerland
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ISO /DTR 7250-4:####(X:(E)
Contents
Foreword .vi i
Introduction . viii
Part 4: Expected performance of skilled anthropometrists . 1
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Background . 2
5 Knowledge expected for experienced anthropometrists . 3
5.1 General . 3
5.2 Landmarking and measurement . 3
5.2.1 Basic knowledge on human anatomy . 3
5.2.2 Correct posture of participant . 4
5.2.3 Landmarking . 4
5.2.4 Instruments and small articles . 4
5.2.5 Role of the assistant . 4
5.2.6 Anthropometric data sheet . 5
5.3 Planning an anthropometric survey . 5
5.3.1 Participants . 5
5.3.2 Measurement items . 5
5.3.3 Measurers and assistants . 5
5.3.4 Space . 6
5.3.5 Schedule of survey . 6
5.3.6 Clothing of participants . 6
5.3.7 Ethical considerations . 6
5.4 Data editing . 7
6 Quantifying measurement errors . 7
6.1 General . 7
6.2 Intra-observer measurement error . 7
6.3 Inter-observer measurement error . 8
6.4 Errors in landmarking . 9
7 Report . 9
Annex A (informative) Example report of intra-observer measurement errors . 10
Annex B (informative) Example report of inter-observer measurement errors . 14
Annex C (informative) Example report of intra-observer errors in landmarking . 16
Bibliography . 29
Foreword iv
Introduction v
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ISO /DTR 7250-4:####(X:(E)
1 Scope 1
2 Normative references 1
3 Terms and definitions 1
4 Background 2
5 Knowledge expected for experienced anthropometrists 3
5.1 General 3
5.2 Landmarking and measurement 3
5.3 Planning an anthropometric survey 5
5.4 Data editing 6
6 Quantifying measurement errors 6
6.1 General 6
6.2 Intra-observer measurement error 7
6.3 Inter-observer measurement error 7
6.4 Errors in landmarking 8
7 Report 8
Annex A (informative) Example report of intra-observer measurement errors 9
Annex B (informative) Example report of inter-observer measurement errors 13
Annex C (informative) Example report of intra-observer errors in landmarking 15
Bibliography 17
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ISO /DTR 7250-4:####(X:(E)
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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documentsdocument should be noted. This document was drafted in accordance
with the editorial rules of the ISO/IEC Directives, Part 2 (see
www.iso.org/directiveswww.iso.org/directives).
Attention is drawnISO draws attention to the possibility that some of the elementsimplementation of this
document may beinvolve the subjectuse of (a) patent(s). ISO takes no position concerning the evidence,
validity or applicability of any claimed patent rights. in respect thereof. As of the date of publication of
this document, ISO had not received notice of (a) patent(s) which may be required to implement this
document. However, implementers are cautioned that this may not represent the latest information,
which may be obtained from the patent database available at www.iso.org/patents. ISO shall not be held
responsible for identifying any or all such patent rights. Details of any patent rights identified during the
development of the document will be in the Introduction and/or on the ISO list of patent declarations
received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the World
Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.htmlwww.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 159, Ergonomics, Subcommittee SC 3,
Anthropometry and biomechanics.
A list of all parts in the ISO 7250 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at
www.iso.org/members.htmlwww.iso.org/members.html.
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ISO /DTR 7250-4:####(X:(E)
Introduction
Anthropometric data used for technological design have been included in many ISO product standards.
There are several standards such as ISO 15535 that refer to a skilled or experienced anthropometrist, but
give no clear information on what is a skilled or experienced anthropometrist. The skill of an
anthropometrist formforms the most important part of quality control of anthropometric data. The
information provided by this technical report complementdocument complements the lack of existing
standards and maycan help developers and users of anthropometric databases.
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ISO/DTR 7250-4:(E)
Basic human body measurements for technological design —
Part 4:
Expected performance of skilled anthropometrists
1 Scope
This part of ISO 7250document describes the knowledge and skillsskill required for an experienced
anthropometrist who serves as a measurer in anthropometric surveys or a planner of an anthropometric
survey. This part of ISO 7250document also describes methods to quantify the skill of anthropometrists
and to report their performance.
This document is not a textbook or manual for anthropometry but maycan be useful for those who plan
and conduct anthropometric surveys as well as designers and technologists who utilize anthropometric
data. Methods described in this document maycan also be applicable to measurements other than those
described in ISO 7250-1.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obphttps://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/https://www.electropedia.org/
3.1
anthropometrist
person who takes scientifically accurate measurements of the human body according to traditional
methods
3.2
inter-observer measurement error
difference between the measurements taken on the same participant by different measurers
3.3
intra-observer measurement error
difference between the repeated measurements taken on the same participant by the same measurer
3.4
anatomical landmark
point clearly defined on the body that can be used for determining anthropometric measurements
[SourceSOURCE: ISO 20685-1:2018, 3.6]
3.5
landmarking
placingplacement of an anatomical landmark point on the skin of a participant by palpating the
underlying bone and/or observing the surface shape of anatomical structures
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ISO/DTR 7250-4:(E)
3.6
bias
systematic difference between two sets of measurements on the same participant group by different
measurers
4 Background
Different factors influence the quality of anthropometric data by the type of data as shown in Table
1.Table 1. In the traditional methods, instruments are simple and easy to calibrate. Body posture is a part
of the definition of a measurement item and is controlled by the measurer when taking measurement.
Since the time duration required for taking a manual measurement is very short, the influence of the body
sway is negligible. Therefore, the skill of the measurer in landmarking and measuring is the main cause
of errors in the traditional methods. Reducing errors in landmarking is essential for reducing errors in
measurements.
Since the human body is not a rigid object, it is impossible to give the true value to a human body.
Therefore, the accuracy of the human body measurement cannot be evaluated. Only the precision of
measurement can be evaluated for manual measurements.
Skill of anthropometry can be obtained only through training. The aim of training is to reduce intra- and
inter-observer measurement errors. The goal of training is to make a trainee into an experienced
anthropometrist. However, self-training that relies solely on textbooks, standards, or other material can
lead to inaccurate landmarking procedures that result in biased landmark positions. Periodic training
with an experienced anthropometrist is necessary.
Scan-derived measurements are influenced by more factors than the 1-D measurements obtained by the
traditional methods. The protocol for quality control of scan-derived measurements is already
standardized (see ISO 20685-1, and ISO 20685-2), except for the protocol for evaluating the performance
of software for automatically calculating landmark positions or measurements.
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ISO/DTR 7250-4:(E)
Table 1 — Factors that maycan influence the quality of anthropometric data
Scan-derived measurements
Traditional body
Factor
Landmark Surface
measurement
Body measurement
coordinate shape
Accuracy of instrument N/A
Hardware
N/A Accuracy of scanner system hardware
Performance of scanner system software (e.g.,. data merging)
Tool
Performance of landmarking software N/A
Software N/A
Performance of measurement
N/A
calculation software
Skill of landmarking N/A
Measurer
Skill of measurement N/A
N/A Skill of deciding landmark position from a marker N/A
Human Operator
Skill of operating measurement
N/A N/A
calculation software
Repeatability of the posture
Participant
N/A Body sway during scan
65 Knowledge expected for experienced anthropometrists
6.15.1 General
Experienced anthropometrists are expected to be able to measure measurements of ISO 7250-1 with
small intra-observer measurement errors, to obtain reliable statistics from the measured data, and to
plan an anthropometric survey. Measuring, obtaining statistics, and planning an anthropometric survey
require different types of knowledge. They are listed in the following clauses.
6.25.2 Landmarking and measurement
The knowledge required for landmarking and measurement includes definitions of landmarks, procedure
to decide positions of landmarks and place the landmarks, how to use and care for instruments,
definitions of measurement items, and procedure to take measurements. They are listed in the following
clauses. More information is available from published textbooks on anthropometry, manual for a survey,
or standards.
6.2.15.2.1 5.2.1 Basic knowledge on human anatomy
Basic knowledge on human anatomy is necessary for understanding the definition of landmarks and their
positions in the human body. Some landmarks are defined on a specific position on a bone (e.g. spinous
process), and some measurements are defined using names of a specific position of a bone (e.g. styloid
process).
Some landmarks defined on the tip of a bone are easier to palpate when the participant bends a joint.
However, the participant is in the posture for measurement when the measurer puts a mark on the skin.
This is because when the joint bends, the skin slides on the bone, and the relative position of the bone
and skin changes.
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ISO/DTR 7250-4:(E)
6.2.35.2.2 5.2.2 Correct posture of participant
Participant posture is part of the definition of a measurement. Correct posture is essential because when
the posture changes, the size of a dimension can also change. For example, shoulder (biacromial) breadth
becomes smaller when arms are abducted; foot dimensions are smaller when participant is sitting rather
than standing; waist circumference is smaller when the abdominal muscles are tight; stature becomes
smaller when participant is not standing erect or larger when participant is in supine position.
The measurer needs to understand the definition of posture and to instruct the participant properly for
him/ or her to take the correct posture.
6.2.45.2.3 5.2.3 Landmarking
When plural measurements defined using the same landmark are measured, position of the landmark is
marked on the skin so that the same location is used for all measurements. An easily removable and non-
toxic marker is used. An eyeliner pencil is often used for this purpose. The size and shape of the mark are
such that it is easily recognized as a point on the skin, and clearly different from moles.
6.2.55.2.4 5.2.4 Instruments and small articles
Instruments used are listed in ISO 7250-1:2017. Small articles used for defining lines or landmarks used
in the apparel are listed in ISO 8559-1:2017, 4.2.
Safety of the participant is the matter of first priority. Measurer needs to take care of the pointed tip of
the arm of anthropometer or sliding calipers.
Two arms of a large sliding caliper need to be the same length when it is used to measure a point-to-point
distance.
Measurer covers the tips of a spreading caliper with fingertips to control the pressure on the participant
skin.
Always use flat-tip-jaws of a sliding caliper. Never use pointed-tip-jaws for measuring people.
When a tape measure is wrapped around the participant, the zero point of the tape measure overlaps the
scale on the tape measure (Figure 1, A).[see Figure 1, a)]. Since the circumference of the trunk influenced
by breathing, the participant is naturally breathing when measured.
When a body scanner is used for obtaining body dimensions, the accuracy of scan-derived body
dimensions needs to be evaluated according to the protocol described in ISO 20685-1:2018, Clause 5.
a) Proper b) Not proper
Figure 1 — How to wrap a tape measure around participant.
6.2.65.2.5 5.2.5 Role of the assistant
MeasurerThe measurer and the assistant work together as a team. AssistantThe assistant helps the
measurer in many ways as described below. MeasurerThe measurer needs to give proper instructions to
the assistant to get effective help from the assistant.
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ISO/DTR 7250-4:(E)
The measurer reads aloud a measurement value, and the assistant writes down the number on the data
sheet. In order to avoid mistakes in reading and/or hearing, the assistant repeats aloud the number
before writing it down. When the number is clearly irregular, the assistant asks the measurer to take
another measurement.
AssistantThe assistant helps the measurer by watching if the anthropometer is vertical and by adjusting
the position of the anthropometer when necessary. When a large circumference of the trunk such as chest
circumference is measured, the assistant holds the tape measure at the back of the participant so that the
position of the tape measure is horizontal and to avoid the tape measure slipping down.
AssistantThe assistant also watches if the posture of the participant is correct (e.g.,. the head is oriented
in the Frankfurt plane).
Basically, the assistant works according to the instructions of the measurer. However, it helps to reduce
the time required for measurement if he/ or she can act as necessary without instruction from the
measurer. If the assistants haveassistant has knowledge on anthropometry, it helps to play theirhis or
her role properly.
6.2.75.2.6 5.2.6 Anthropometric data sheet
Anthropometric data sheets are designed so that there are blanks for all necessary information.
Measurement items are ordered to minimize the required time for measurements and to minimize the
errors due to mistakes. Recommended background data on the survey are listed in ISO/FDIS 15535:2023,
1
7.2 . Necessary background information items on each participant are listed in ISO/FDIS 15535:2023,
Annex B. An example data sheet is in ISO/FDIS 15535:2023, Annex C.
6.35.3 Planning an anthropometric survey
6.3.15.3.1 5.3.1 Participants
Decide theThe target population (gender, age range, and other background whenas necessary) and the
number of participants are selected according to the purpose of the survey. A method to estimate the
number of participants required to have a particular confidence at 5th and 95th percentiles is described
in ISO/FDIS 15535:2023, Annex A.
Decide theThe method of recruiting participants is selected.
6.3.25.3.2 5.3.2 Measurement items
Decide measurementMeasurement items are selected according to the purpose of the survey and confirm
landmarks necessary to take these measurements. Decide instruments are confirmed. Instruments and
small articles necessary for landmarking and measurement. are selected.
Estimate theThe time required for measuring one participant is estimated.
6.3.35.3.3 5.3.3 Measurers and assistants
When the number of measurement items is too large for one measurer, divide the measurement items
are divided into several groups and allocate each group of measurement items are allocated to a different
measurer. This reduces the burden on measurers and assistants and saves time for measurement since
more participants can be measured at the same time.
Decide theThe number of measurers and assistants are selected considering the load on each measurer
and allocate measurement items are allocated to each measurer. Estimate theThe number of participants
measured in one day is estimated.
One or more persons other than measurers and assistants are necessary to guide participants and to
handle unexpected thingsevents during survey.
1
Under preparation. Stage at the time of publication: ISO/FDIS 15535:2023.
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ISO/DTR 7250-4:(E)
6.3.45.3.4 5.3.4 Space
Prepare theThe space is prepared for obtaining informed consent, changing room, measuring room, and
resting room in case participant becomesparticipants become ill.
Prepare separateSeparate or partitioned measuring booths are prepared for each measuring team for
protecting the privacy of the participants.
6.3.55.3.5 5.3.5 Schedule of survey
Estimate theThe number of days more than sufficient is estimated to measure all participants.
6.3.65.3.6 5.3.6 Clothing of participants
According to ISO 7250-1:2017, 4.1, “the participant shall be nude or shall wear only minimal clothing and
shall be bareheaded and without shoes”. Select culturallyCulturally permissible clothing suitable for the
purpose of the survey is selected. Conditions of desirable scanning attire are described in ISO 20685-
1:2018, Annex A.
Prepare differentDifferent sizes of clothing that satisfy participants belonging to the target population.
are prepared.
Decide ifA decision is made on whether the clothing is washed and reused or used only once. If reused,
prepare extra clothing for use is prepared while other clothes are being washed.
Prepare something looseLoose clothing to wear is prepared while the participant moves to the next booth
if necessary.
6.3.75.3.7 5.3.7 Ethical considerations
Many institutions have an ethical committee for the purpose of protecting the rights of the participants.
A plan of an anthropometric survey is reviewed and approved by an institutional ethical committee.
Consider issuesIssues such as the following are considered when planning an anthropometric survey.
a) (1) Protection of participantparticipants
Participants wear only minimal clothing during anthropometry. Design theThe space for anthropometry
is designed to protect the privacy of the participant.
Minimize theThe measurement time is minimized so that the participant woulddoes not beget tired.
Insert restingResting time is inserted between sessions as necessary.
Prepare aA place for rest is prepared in case the participant becomes ill.
b) (2) Informed consent
Obtain informedInformed consent is obtained from each participant before starting measurement.
c) (3) Protection of measurers and assistants
Avoid tightTight schedule is avoided so that the working time in a day is not too long for measurer-
assistant teams. Insert restingResting time is inserted between sessions if necessary.
When many measurement items are taken, and multiple measurers participate, allocate measurements
are allocated appropriately to measurer-assistant teams to reduce the burden on each team.
d) (4) Gender
Best practice is that measurers and assistants are of the same gender as the participant.
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ISO/DTR 7250-4:(E)
6.55.4 Data editing
It is inevitable that measurements collected by the traditional methods have irregular values caused by
mistakes. These irregular values must beare corrected or removed before statistical analysis. Procedure
for data editing is standardized in ISO/FDIS 15535:2023, Annex F.
Most of the errors caused by mistakes are not outliers that exceed the mean ± 3 standard deviations. Such
errors may notcannot affect the mean but can affect statistics such as correlation coefficient. To identify
such irregular values, procedure using a scatter diagram as described in ISO/FDIS 15535:2023, Annex F
is necessary.
76 Quantifying measurement errors
7.16.1 General
The skill of a measurer can be quantified by using indicator(s) of intra-observer measurement error.
Comparability between two measurers can be also quantified using some of these indicators. The
protocol described in ISO 20685-1:2018, Clause 5 is applicable to evaluate the comparability of
measurements taken by two different measures.
7.26.2 Intra-observer measurement error
Indicators of intra-observer measurement error can be obtained through an experiment, in which an
observer measures each of N participants twice. In the experimen
...
FINAL
TECHNICAL ISO/DTR
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REPORT 7250-4
ISO/TC 159/SC 3
Basic human body measurements for
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Expected performance of skilled
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ISO/DTR 7250-4:2023(E)
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ISO/TC 159/SC 3
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NATIONAL REGULATIONS. © ISO 2023
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ISO/DTR 7250-4:2023(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Background . 2
5 Knowledge expected for experienced anthropometrists . 3
5.1 General . 3
5.2 Landmarking and measurement . 3
5.2.1 Basic knowledge on human anatomy . . 3
5.2.2 Correct posture of participant . 3
5.2.3 Landmarking . 3
5.2.4 Instruments and small articles . 3
5.2.5 Role of the assistant. 4
5.2.6 Anthropometric data sheet . 4
5.3 Planning an anthropometric survey . 5
5.3.1 Participants. 5
5.3.2 Measurement items . 5
5.3.3 Measurers and assistants . 5
5.3.4 Space . . . 5
5.3.5 Schedule of survey . 5
5.3.6 Clothing of participants . 5
5.3.7 Ethical considerations . 6
5.4 Data editing . 6
6 Quantifying measurement errors .6
6.1 General . 6
6.2 Intra-observer measurement error . 6
6.3 Inter-observer measurement error. 8
6.4 Errors in landmarking . 8
7 Report . 8
Annex A (informative) Example report of intra-observer measurement errors .10
Annex B (informative) Example report of inter-observer measurement errors .13
Annex C (informative) Example report of intra-observer errors in landmarking .14
Bibliography .16
iii
© ISO 2023 – All rights reserved
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ISO/DTR 7250-4:2023(E)
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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO document should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 159, Ergonomics, Subcommittee SC 3,
Anthropometry and biomechanics.
A list of all parts in the ISO 7250 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
© ISO 2023 – All rights reserved
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ISO/DTR 7250-4:2023(E)
Introduction
Anthropometric data used for technological design have been included in many ISO product standards.
There are several standards such as ISO 15535 that refer to a skilled or experienced anthropometrist
but give no clear information on what is a skilled or experienced anthropometrist. The skill of an
anthropometrist forms the most important part of quality control of anthropometric data. The
information provided by this document complements the lack of existing standards and can help
developers and users of anthropometric databases.
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TECHNICAL REPORT ISO/DTR 7250-4:2023(E)
Basic human body measurements for technological
design —
Part 4:
Expected performance of skilled anthropometrists
1 Scope
This document describes the knowledge and skill required for an experienced anthropometrist
who serves as a measurer in anthropometric surveys or a planner of an anthropometric survey.
This document also describes methods to quantify the skill of anthropometrists and to report their
performance.
This document is not a textbook or manual for anthropometry but can be useful for those who plan and
conduct anthropometric surveys as well as designers and technologists who utilize anthropometric
data. Methods described in this document can also be applicable to measurements other than those
described in ISO 7250-1.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
anthropometrist
person who takes scientifically accurate measurements of the human body according to traditional
methods
3.2
inter-observer measurement error
difference between the measurements taken on the same participant by different measurers
3.3
intra-observer measurement error
difference between the repeated measurements taken on the same participant by the same measurer
3.4
anatomical landmark
point clearly defined on the body that can be used for determining anthropometric measurements
[SOURCE: ISO 20685-1:2018, 3.6]
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ISO/DTR 7250-4:2023(E)
3.5
landmarking
placement of an anatomical landmark point on the skin of a participant by palpating the underlying
bone and/or observing the surface shape of anatomical structures
3.6
bias
systematic difference between two sets of measurements on the same participant group by different
measurers
4 Background
Different factors influence the quality of anthropometric data by the type of data as shown in Table 1.
In the traditional methods, instruments are simple and easy to calibrate. Body posture is a part of the
definition of a measurement item and is controlled by the measurer when taking measurement. Since
the time duration required for taking a manual measurement is very short, the influence of the body
sway is negligible. Therefore, the skill of the measurer in landmarking and measuring is the main cause
of errors in the traditional methods. Reducing errors in landmarking is essential for reducing errors in
measurements.
Since the human body is not a rigid object, it is impossible to give the true value to a human body.
Therefore, the accuracy of the human body measurement cannot be evaluated. Only the precision of
measurement can be evaluated for manual measurements.
Skill of anthropometry can be obtained only through training. The aim of training is to reduce intra-
and inter-observer measurement errors. The goal of training is to make a trainee into an experienced
anthropometrist. However, self-training that relies solely on textbooks, standards or other material can
lead to inaccurate landmarking procedures that result in biased landmark positions. Periodic training
with an experienced anthropometrist is necessary.
Scan-derived measurements are influenced by more factors than the 1-D measurements obtained by
the traditional methods. The protocol for quality control of scan-derived measurements is already
standardized (see ISO 20685-1 and ISO 20685-2), except for the protocol for evaluating the performance
of software for automatically calculating landmark positions or measurements.
Table 1 — Factors that can influence the quality of anthropometric data
Scan-derived measurements
Traditional body meas-
Factor
Landmark coor- Surface
urement
Body measurement
dinate shape
Accuracy of instrument N/A
Hardware
N/A Accuracy of scanner system hardware
Performance of scanner system software (e.g. data merging)
Tool
Performance of landmarking software N/A
Software N/A
Performance of measurement
N/A
calculation software
Skill of landmarking N/A
Measurer
Skill of measurement N/A
N/A Skill of deciding landmark position from a marker N/A
Human Operator
Skill of operating measure-
N/A N/A
ment calculation software
Repeatability of the posture
Participant
N/A Body sway during scan
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ISO/DTR 7250-4:2023(E)
5 Knowledge expected for experienced anthropometrists
5.1 General
Experienced anthropometrists are expected to be able to measure measurements of ISO 7250-1 with
small intra-observer measurement errors, to obtain reliable statistics from the measured data, and to
plan an anthropometric survey. Measuring, obtaining statistics and planning an anthropometric survey
require different types of knowledge. They are listed in the following clauses.
5.2 Landmarking and measurement
The knowledge required for landmarking and measurement includes definitions of landmarks,
procedure to decide positions of landmarks and place the landmarks, how to use and care for
instruments, definitions of measurement items, and procedure to take measurements. They are listed
in the following clauses. More information is available from published textbooks on anthropometry,
manual for a survey, or standards.
5.2.1 Basic knowledge on human anatomy
Basic knowledge on human anatomy is necessary for understanding the definition of landmarks and
their positions in the human body. Some landmarks are defined on a specific position on a bone (e.g.
spinous process), and some measurements are defined using names of a specific position of a bone (e.g.
styloid process).
Some landmarks defined on the tip of a bone are easier to palpate when the participant bends a joint.
However, the participant is in the posture for measurement when the measurer puts a mark on the skin.
This is because when the joint bends, the skin slides on the bone, and the relative position of the bone
and skin changes.
5.2.2 Correct posture of participant
Participant posture is part of the definition of a measurement. Correct posture is essential because
when the posture changes, the size of a dimension can also change. For example, shoulder (biacromial)
breadth becomes smaller when arms are abducted; foot dimensions are smaller when participant is
sitting rather than standing; waist circumference is smaller when the abdominal muscles are tight;
stature becomes smaller when participant is not standing erect or larger when participant is in supine
position.
The measurer needs to understand the definition of posture and to instruct the participant properly for
him or her to take the correct posture.
5.2.3 Landmarking
When plural measurements defined using the same landmark are measured, position of the landmark
is marked on the skin so that the same location is used for all measurements. An easily removable and
non-toxic marker is used. An eyeliner pencil is often used for this purpose. The size and shape of the
mark are such that it is easily recognized as a point on the skin, and clearly different from moles.
5.2.4 Instruments and small articles
Instruments used are listed in ISO 7250-1. Small articles used for defining lines or landmarks used in
the apparel are listed in ISO 8559-1:2017, 4.2.
Safety of the participant is the matter of first priority. Measurer needs to take care of the pointed tip of
the arm of anthropometer or sliding calipers.
Two arms of a large sliding caliper need to be the same length when it is used to measure a point-to-
point distance.
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ISO/DTR 7250-4:2023(E)
Measurer covers the tips of a spreading caliper with fingertips to control the pressure on the participant
skin.
Always use flat-tip-jaws of a sliding caliper. Never use pointed-tip-jaws for measuring people.
When a tape measure is wrapped around the participant, the zero point of the tape measure overlaps
the scale on the tape measure [see Figure 1, a)]. Since the circumference of the trunk influenced by
breathing, the participant is naturally breathing when measured.
When a body scanner is used for obtaining body dimensions, the accuracy of scan-derived body
dimensions needs to be evaluated according to the protocol described in ISO 20685-1:2018, Clause 5.
a) Proper b) Not proper
Figure 1 — How to wrap a tape measure around participant
5.2.5 Role of the assistant
The measurer and the assistant work together as a team. The assistant helps the measurer in many
ways as described below. The measurer needs to give proper instructions to the assistant to get
effective help from the assistant.
The measurer reads aloud a measurement value, and the assistant writes down the number on the data
sheet. In order to avoid mistakes in reading and/or hearing, the assistant repeats aloud the number
before writing it down. When the number is clearly irregular, the assistant asks the measurer to take
another measurement.
The assistant helps the measurer by watching if the anthropometer is vertical and by adjusting the
position of the anthropometer when necessary. When a large circumference of the trunk such as chest
circumference is measured, the assistant holds the tape measure at the back of the participant so that
the position of the tape measure is horizontal and to avoid the tape measure slipping down.
The assistant also watches if the posture of the participant is correct (e.g. the head is oriented in the
Frankfurt plane).
Basically, the assistant works according to the instructions of the measurer. However, it helps to reduce
the time required for measurement if he or she can act as necessary without instruction from the
measurer. If the assistant has knowledge on anthropometry, it helps to play his or her role properly.
5.2.6 Anthropometric data sheet
Anthropometric data sheets are designed so that there are blanks for all necessary information.
Measurement items are ordered to minimize the required time for measurements and to minimize the
errors due to mistakes. Recommended background data on the survey are listed in ISO 15535:2023,
1)
7.2 . Necessary background information items on each participant are listed in ISO 15535:2023,
Annex B. An example data sheet is in ISO 15535:2023, Annex C.
1) Under preparation. Stage at the time of publication: ISO/FDIS 15535:2023.
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ISO/DTR 7250-4:2023(E)
5.3 Planning an anthropometric survey
5.3.1 Participants
The target population (gender, age range and other background as necessary) and the number of
participants are selected according to the purpose of the survey. A method to estimate the number
of participants required to have a particular confidence at 5th and 95th percentiles is described in
ISO 15535:2023, Annex A.
The method of recruiting participants is selected.
5.3.2 Measurement items
Measurement items are selected according to the purpose of the survey and landmarks necessary to
take these measurements are confirmed. Instruments and small articles necessary for landmarking
and measurement are selected.
The time required for measuring one participant is estimated.
5.3.3 Measurers and assistants
When the number of measurement items is too large for one measurer, the measurement items are
divided into several groups and each group of measurement items are allocated to a different measurer.
This reduces the burden on measurers and assistants and saves time for measurement since more
participants can be measured at the same time.
The number of measurers and assistants are selected considering the load on each measurer and
measurement items are allocated to each measurer. The number of participants measured in one day is
estimated.
One or more persons other than measurers and assistants are necessary to guide participants and to
handle unexpected events during survey.
5.3.4 Space
The space is prepared for obtaining informed consent, changing room, measuring room and resting
room in case participants become ill.
Separate or partitioned measuring booths are prepared for each measuring team for protecting the
privacy of the participants.
5.3.5 Schedule of survey
The number of days more than sufficient is estimated to measure all participants.
5.3.6 Clothing of participants
According to ISO 7250-1:2017, 4.1, “the participant shall be nude or shall wear only minimal clothing
and shall be bareheaded and without shoes”. Culturally permissible clothing suitable for the purpose
of the survey is selected. Conditions of desirable scanning attire are described in ISO 20685-1:2018,
Annex A.
Different sizes of clothing that satisfy participants belonging to the target population are prepared.
A decision is made on whether the clothing is washed and reused or used only once. If reused, extra
clothing for use is prepared while other clothes are being washed.
Loose clothing to wear is prepared while the participant moves to the next booth if necessary.
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ISO/DTR 7250-4:2023(E)
5.3.7 Ethical considerations
Many institutions have an ethical committee for the purpose of protecting the rights of the participants.
A plan of an anthropometric survey is reviewed and approved by an institutional ethical committee.
Issues such as the following are considered when planning an anthropometric survey.
a) Protection of participants
Participants wear only minimal clothing during anthropometry. The space for anthropometry is
designed to protect the privacy of the participant.
The measurement time is minimized so that the participant does not get tired. Resting time is inserted
between sessions as necessary.
A place for rest is prepared in case the participant becomes ill.
b) Informed consent
Informed consent is obtained from each participant before starting measurement.
c) Protection of measurers and assistants
Tight schedule is avoided so that the working time in a day is not too long for measurer-assistant teams.
Resting time is inserted between sessions if necessary.
When many measurement items are taken, and multiple measurers participate, measurements are
allocated appropriately to measurer-assistant teams to reduce the burden on each team.
d) Gender
Best practice is that measurers and assistants are of the same gender as the participant.
5.4 Data editing
It is inevitable that measurements collected by the traditional methods have irregular values caused
by mistakes. These irregular values are corrected or removed before statistical analysis. Procedure for
data editing is standardized in ISO 15535:2023, Annex F.
Most of the errors caused by mistakes are not outliers that exceed the mean ±3 standard deviations.
Such errors cannot affect the mean but can affect statistics such as correlation coefficient. To identify
such irregular values, procedure using a scatter diagram as described in ISO 15535:2023, Annex F is
necessary.
6 Quantifying measurement errors
6.1 General
The skill of a measurer can be quantified by using indicator(s) of intra-observer measurement
error. Comparability between two measurers can be also quantified using some of these indicators.
The protocol described in ISO 20685-1:2018, Clause 5 is applicable to evaluate the comparability of
measurements taken by two different measures.
6.2 Intra-observer measurement error
Indicators of intra-observer measurement error can be obtained through an experiment, in which an
observer measures each of N participants twice. In the experiment, sufficient time is inserted between
the two measurements in order to avoid the measurer remembering the former value.
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ISO/DTR 7250-4:2023(E)
Measurement of participant-i measured by a measurer, x , can be described as Formula (1),
i
x = M + P + O + e (1)
i i i
where
M
is the mean of the population;
P
is the characteristic of participant-i;
i
O is the bias of the observer;
e is random error.
i
Intra-observer error, the difference between two repeated measurements of participant-i measured by
the measurer, is d , and described by Formula (2).
i
d = x – x = e – e (2)
i i1 i2 i1 i2
where
x
is the first measurement;
i1
x
is the second measurement.
i2
Since M, P and O are cancelled out, the intra-observer error depends only on the random error, and
i
mean of d is 0. However, variance of d is not 0.
i i
The magnitude of the intra-observer error is often quantified by mean absolute difference (MAD),
described as Formula (3), where N is the number of participants.
Another indicator of the intra-observer error is technical error of measurement (TEM) calculated as
Formula (4). TEM is the square root of the variance of random error. Both MAD and TEM are described
in the unit of measurement (mm or kg).
X absdiff = ∑|d |/n (3)
i
2
S = √[∑(d )/2n] (4)
diff i
where
is the mean absolute difference, MAD;
X
absdiff
S is the technical error of measurement, TEM;
diff
n is the number of participants.
The percentage of random error variance is calculated by dividing the square of TEM by the square of
the standard deviation of measurement x.
Correlation coefficient between repeated measurements represents the linear relationship between
the two repeated measurements and can be used to quanti
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