EN ISO 10551:2019

Ergonomics of the physical environment - Subjective judgement scales for assessing physical environments (ISO 10551:2019)

This document presents principles and examples of practical application for the construction of appropriate subjective scales for use in the assessment and evaluation of the physical environment. It does not standardize particular scales.
It considers scales of perception, comfort, preference, acceptability, expression form and tolerance, and environmental components such as thermal, visual, air quality, acoustic and vibration.
It does not consider other scales such as:
—         scales related to the effects of the environment on the ability to read displays or signs, on manual performance or on psychological conditions such as mood, etc.;
—         scales related to pain or scales related to stimuli that can lead to injury.
This document does not present principles of surveys (see Note) or questionnaire design. However, the scales that are developed using this document can be incorporated into surveys or questionnaires.
NOTE       Environmental surveys are described in ISO 28802. ISO 28802 includes scales that are complementary to, and based upon, the principles of scale construction that are described in this document.

Ergonomie des Umgebungsklimas - Subjektive Bewertungsskalen für die Beurteilung der physikalischen Umgebung (ISO 10551:2019)

Dieses Dokument stellt Grundsätze und Beispiele der praktischen Anwendung für die Erstellung geeigneter subjektiver Skalen für den Einsatz bei der Beurteilung und Bewertung der physikalischen Umgebung vor. Es standardisiert keine bestimmten Skalen.
Es berücksichtigt Skalen in Bezug auf Wahrnehmung, Komfort, Präferenzen, Annehmbarkeit, Ausdrucksform und Toleranz sowie Umgebungseigenschaften wie etwa Temperatur, Licht, Luftqualität, Akustik und Vibration.
Es berücksichtigt keine anderweitigen Skalen wie etwa:
- Skalen zu Auswirkungen der Umgebung auf die Fähigkeit, Anzeigen oder Schilder zu lesen, auf manuelle Leistungen oder auf psychologische Zustände wie Stimmung usw.;
- Skalen in Zusammenhang mit Schmerzen oder Reizen, die zu einer Verletzung führen können.
Dieses Dokument liefert keine Grundsätze für die Gestaltung von Umfragen (siehe Anmerkung) oder Fragebögen. Jedoch können die im Rahmen dieses Dokuments entwickelten Skalen in Umfragen oder Fragebögen integriert werden.
ANMERKUNG Umfragen zu Umgebungen sind in ISO 28802 beschrieben. ISO 28802 umfasst Skalen, die auf den Grundsätzen der Skalenerstellung basieren und diese ergänzen, die in diesem Dokument beschrieben sind.

Ergonomie de l'environnement physique - Échelles de jugements subjectifs pour l'évaluation des environnements physiques (ISO 10551:2019)

Le présent document donne les principes ainsi que des exemples d'application pratique pour la construction d'échelles subjectives appropriées servant à l'évaluation et à l'appréciation de l'environnement physique. Il ne normalise pas les échelles particulières.
Il couvre les échelles de perception, de confort, de préférence, d'acceptabilité, de forme d'expression et de tolérance, et les aspects environnementaux tels que l'aspect thermique, l'aspect visuel, la qualité de l'air, l'acoustique et les vibrations.
Il ne couvre pas les autres échelles telles que:
—         les échelles relatives aux effets de l'environnement sur la capacité de lecture des affichages ou des panneaux, sur les performances manuelles ou sur l'état psychologique comme le moral, etc.;
—         les échelles relatives à la douleur ou les échelles relatives aux stimuli susceptibles d'entraîner une blessure.
Le présent document ne présente pas les principes des enquêtes (voir Note) ni de conception des questionnaires. Cependant, les échelles qui sont élaborées en utilisant le présent document peuvent être intégrées dans les enquêtes ou les questionnaires.
NOTE       Les enquêtes environnementales sont décrites dans l'ISO 28802. L'ISO 28802 inclut des échelles qui viennent compléter ou s'appuyer sur les principes de construction des échelles qui sont décrits dans le présent document.

Ergonomija fizičnega okolja - Subjektivne lestvice za presojo fizičnih okolij (ISO 10551:2019)

Standard EN-ISO 10551 podaja pristope in primere praktične uporabe za izdelavo ustrezne subjektivne lestvice za presojo ter ocenjevanje fizičnih okolij. Ne standardizira določene lestvice. Upošteva lestvice zaznavanja, udobja, prednostne izbire, sprejemljivosti, oblike izražanja in tolerance ter okoljske elemente, kot so temperatura, vidljivost, kakovost zraka, akustika in vibracije. Ne upošteva pa drugih lestvic, kot so: – lestvice, povezane z učinki okolja na zmožnost branja prikazov ali znakov, na ročne zmogljivosti ali na psihološka stanja, kot je razpoloženje itd.; – lestvice, povezane z bolečino, ali lestvice, povezane z dražljaji, ki lahko privedejo do telesnih poškodb. Ta dokument ne podaja načel za načrtovanje anket (glej opombo) ali vprašalnikov. Vendar pa je v ankete ali vprašalnike mogoče vključiti lestvice, izdelane na podlagi tega dokumenta.

General Information

• Status: Published
• Publication Date: 30-Oct-2019
• Withdrawal Date: 30-Jan-2020
• ICS: 13.180 - Ergonomics
• Technical Committee: CEN/TC 122 - Ergonomics
• Drafting Committee: CEN/TC 122/WG 11 - Ergonomics of the Physical Environment
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 31-Jul-2019
• Completion Date: 31-Jul-2019
• Ref Project: SIST EN ISO 10551:2020 - Ergonomics of the physical environment - Subjective judgement scales for assessing physical environments (ISO 10551:2019)

Relations

• Replaces: EN ISO 10551:2001 - Ergonomics of the thermal environment - Assessment of the influence of the thermal environment using subjective judgement scales (ISO 10551:1995)
• Effective Date: 08-Jun-2022

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 10551:2020
01-februar-2020
Nadomešča:
SIST EN ISO 10551:2002

Ergonomija fizičnega okolja - Subjektivne lestvice za presojo fizičnih okolij (ISO

10551:2019)

Ergonomics of the physical environment - Subjective judgement scales for assessing

physical environments (ISO 10551:2019)
Ergonomie des Umgebungsklimas - Subjektive Bewertungsskalen für die Beurteilung
des Umgebungsklimas (ISO 10551:2019)
Ergonomie de l'environnement physique - Échelles de jugements subjectifs pour
l'évaluation des environnements physiques (ISO 10551:2019)
Ta slovenski standard je istoveten z: EN ISO 10551:2019
ICS:
13.180 Ergonomija Ergonomics
SIST EN ISO 10551:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 10551:2020
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SIST EN ISO 10551:2020
EN ISO 10551
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2019
EUROPÄISCHE NORM
ICS 13.180 Supersedes EN ISO 10551:2001
English Version
Ergonomics of the physical environment - Subjective
judgement scales for assessing physical environments (ISO
10551:2019)

Ergonomie de l'environnement physique - Échelles de Ergonomie des Umgebungsklimas - Subjektive

jugements subjectifs pour l'évaluation des Bewertungsskalen für die Beurteilung des

environnements physiques (ISO 10551:2019) Umgebungsklimas (ISO 10551:2019)
This European Standard was approved by CEN on 29 June 2019.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 10551:2019 E

worldwide for CEN national Members.
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SIST EN ISO 10551:2020
EN ISO 10551:2019 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 10551:2020
EN ISO 10551:2019 (E)
European foreword

This document (EN ISO 10551:2019) has been prepared by Technical Committee ISO/TC 159

"Ergonomics" in collaboration with Technical Committee CEN/TC 122 “Ergonomics” the secretariat of

which is held by DIN.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by January 2020, and conflicting national standards shall

be withdrawn at the latest by January 2020.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN ISO 10551:2001.

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
Endorsement notice

The text of ISO 10551:2019 has been approved by CEN as EN ISO 10551:2019 without any modification.

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SIST EN ISO 10551:2020
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SIST EN ISO 10551:2020
INTERNATIONAL ISO
STANDARD 10551
Second edition
2019-06
Ergonomics of the physical
environment — Subjective judgement
scales for assessing physical
environments
Ergonomie de l'environnement physique — Échelles de jugements
subjectifs pour l'évaluation des environnements physiques
Reference number
ISO 10551:2019(E)
ISO 2019
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SIST EN ISO 10551:2020
ISO 10551:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

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 be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
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SIST EN ISO 10551:2020
ISO 10551:2019(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Subjective judgement scales for physical environments: Principles of scale

construction and use ........................................................................................................................................................................................ 1

5 Perceptual, evaluation and preferential judgement scales ..................................................................................... 2

5.1 Instructions for using the judgement scales ................................................................................................................. 2

5.2 Scale of perception of the personal state ......................................................................................................................... 4

5.2.1 Structure of the scale.................................................................................................................................................... 4

5.2.2 Wording of the degrees .............................................................................................................................................. 4

5.3 Evaluative scale ...................................................................................................................................................................................... 4

5.3.1 Structure of the scale.................................................................................................................................................... 4

5.3.2 Wording of the points .................................................................................................................................................. 5

5.4 Preference scale ..................................................................................................................................................................................... 5

5.4.1 Structure of the scale.................................................................................................................................................... 5

5.4.2 Wording of the degrees .............................................................................................................................................. 5

6 Personal acceptability statement and tolerance scale .................................................................................................. 5

6.1 General ........................................................................................................................................................................................................... 5

6.2 Instructions for using the judgement expression forms ..................................................................................... 5

6.3 Description of the forms of judgement expression ................................................................................................. 6

6.3.1 Structure of the forms of judgement expression.................................................................................. 6

6.3.2 Wording of the degrees .............................................................................................................................................. 6

7 Instructions for repeat enquiries ....................................................................................................................................................... 6

8 Summary of the scales .................................................................................................................................................................................... 7

9 Format and method of presentations of the scales ........................................................................................................... 7

10 Data analysis and application of the results ............................................................................................................................ 7

Annex A (informative) Commonly used scales for assessing thermal environments ........................................8

Annex B (informative) Commonly used scales for assessing acoustic environments ....................................11

Annex C (informative) Commonly used scales for assessing visual environments ...........................................13

Annex D (informative) Commonly used scales for assessing vibration environments .................................15

Annex E (informative) Commonly used scales for assessing air quality environments ...............................17

Annex F (informative) Application of assessment procedure and judgement scales:

Examples, including data analysis...................................................................................................................................................18

Annex G (informative) Examples of scales that can be used in the environmental

ergonomics survey ..........................................................................................................................................................................................26

Bibliography .............................................................................................................................................................................................................................28

© ISO 2019 – All rights reserved iii
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SIST EN ISO 10551:2020
ISO 10551:2019(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 documents 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).

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. 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 .html.

This document was prepared by Technical Committee ISO/TC 159, Ergonomics, Subcommittee SC 5,

Ergonomics of the physical environment.

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.

This second edition cancels and replaces the first edition (ISO 10551:1995), which has been technically

revised. The main changes compared to the previous edition are as follows:
— the title has been changed;
— the Scope has been reworded;
— new references have been added to Clause 2;
— new entries have been added to Clause 3;
— in 5.2.1, a unipolar scale has been added;
— Annex B has been changed;
— Annexes C to G have been added.
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Introduction

By using this document, you can construct subjective scales that can be used to ask people how they feel

about their physical environment. That is whether they find it too hot, whether there is any noise and

if it is annoying, if the light is too bright, is it “smelly” and so on. By constructing the scales and using

them correctly, you can see, in a cost-effective way, how people find the environment. The information

can be applied to report on the environmental quality and to work out how to improve the environment.

People are exposed to a range of physical environments which can affect their health and safety,

comfort and performance. An important method for assessing physical environments, particularly

when considering psychological constructs such as comfort or satisfaction, is to use subjective scales.

The type of scale used and how it is administered is important in influencing the subjective responses of

people. There are principles for constructing scales and procedures for administering them that reduce

bias and ensure validity and reliability of response. There are also generic types of scale that can be

used across environmental stimuli, for example, scales on which people rate sensation or comfort or

acceptability or preference and so on.

This document provides a description of principles of scale construction and procedures for use. It also

provides examples of commonly used scales across environmental components. This document does

not standardize any particular scale but it provides the principles upon which appropriate scales can

be constructed. It is needed to provide consistency in the production of valid and reliable scales. It is

particularly useful to people who wish to conduct an environmental survey, for example to assess post

occupant satisfaction of new or existing buildings or other spaces, environments where dissatisfaction

occurs and a diagnosis of the problems is required and for people who are investigating the relationship

between conditions in the physical environment and human perception. A consistent approach to

subjective scale construction and use also allows a meaningful comparison of data obtained from

investigations internationally.

This document forms part of a group of international standards on the assessment of comfort, stress

and strain in physical environments.
This series is concerned, in particular, with:

1) establishing specifications on methods for measuring and estimating the characteristic physical

parameters of environments;
2) establishing methods for assessing stress in environments.

This document proposes a set of specifications on direct expert assessment of comfort/discomfort

expressed by persons subjected to various degrees of stress during periods spent in physical

environments. The data provided by this assessment can be used on its own or to supplement physical

and physiological methods of assessing loads. The methods belong to a psychological approach

consisting in gathering, as appropriate, the on-site opinions of persons exposed to the conditions under

consideration (diagnosis) and, thus, can complement data provided by predictive approaches described

elsewhere in this group. The information provided in this document can be used to construct valid

subjective scales for use in determining how people feel in their physical environment. This document

does not give guidance on questionnaire design and application although the scales may be used in the

construction of questionnaires.

If persons exposed to environments are to be asked about their corresponding experiences or

information requested on their cultural attitude in order to obtain the most appropriate subjective

judgement scales, favourable relationships may usefully be established between these persons and the

organization responsible, through the persons conducting the ergonomic investigation.

The environments which lend themselves to the application of subjective judgement scales relate to

conditions which differ to a moderate degree from comfortable conditions. Under extreme conditions,

physical and physiological assessment methods of the environmental load are preferred, provided

that their results can be used as criteria for a decision. In particular, tolerance limits for load cannot

be confidently based on subjective judgements and need to be decided in view of accepted health risk

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SIST EN ISO 10551:2020
ISO 10551:2019(E)

criteria. The decision of whether a person is exposed to an extreme environment is not left to the person

exposed as their judgement can be impaired by the conditions.

The opinions held by persons about their environment have a value in themselves. It is up to the ergonomist

whether or not to take them into account. The reputation of these data for lack of reliability does not

justify dismissing them out of hand. The aim of this document is precisely to improve their reliability by

specifying the appropriate tools to use in collecting them and the requirement for using them.

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SIST EN ISO 10551:2020
INTERNATIONAL STANDARD ISO 10551:2019(E)
Ergonomics of the physical environment — Subjective
judgement scales for assessing physical environments
1 Scope

This document presents principles and examples of practical application for the construction of

appropriate subjective scales for use in the assessment and evaluation of the physical environment. It

does not standardize particular scales.

It considers scales of perception, comfort, preference, acceptability, expression form and tolerance, and

environmental components such as thermal, visual, air quality, acoustic and vibration.

It does not consider other scales such as:

— scales related to the effects of the environment on the ability to read displays or signs, on manual

performance or on psychological conditions such as mood, etc.;
— scales related to pain or scales related to stimuli that can lead to injury.

This document does not present principles of surveys (see Note) or questionnaire design. However, the

scales that are developed using this document can be incorporated into surveys or questionnaires.

NOTE Environmental surveys are described in ISO 28802. ISO 28802 includes scales that are complementary

to, and based upon, the principles of scale construction that are described in this document.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 13731, Ergonomics of the thermal environment — Vocabulary and symbols
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 13731 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
4 Subjective judgement scales for physical environments: Principles of scale
construction and use

There are a number of subjective judgement scales for physical environments. They differ in whether

emphasis is placed on some aspect of judgement:
— perceptual or affective (evaluative and preferential);
— global (encompassing the whole environment or organism) or localized;
— present or past;
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SIST EN ISO 10551:2020
ISO 10551:2019(E)
— instantaneous or extended over a period of time.

They also differ as to the object of judgement: environment or person, the whole or its component parts,

permanent or temporary situation.

This document retains judgements that people make about their own state as a whole. It distinguishes

between perception, present affective assessment (comfort/discomfort) and future preference.

NOTE 1 This document also suggests supplementing the perceptual, evaluative and preferential judgement

scales by a statement of acceptability and a scale of tolerance of environments

In most instances, the exposure to an environment lasts for several hours. Therefore, it is useful to

gather the person’s opinions throughout, by repeating the expression of the judgements at regular

intervals, using exactly the same scales.

By repeatedly applying the same scales, the evolution with time of the comfort or strain experienced

can be assessed and an integrated judgement obtained over the whole time of exposure by appropriate

computation of the data (e.g. overall mean, overall change, variation, etc.).

Basic difficulties are encountered in any area which involves the use of language. In this regard, bias

and variability in the data can result from inconsistencies and inappropriateness of accompanying

instructions. Therefore, it becomes crucial to standardized preparatory instructions which explain the

study, as well as the wording of the judgement scales. The terminology used to denote the degrees on

the judgement scales is of special importance. This document specifies the principles used to develop

subjective scales. The actual descriptors used can be influenced by the language structure and shall be

established with subject experts from National Standards Body.

NOTE 2 International usage and acceptance of the scales in this document will result in the fixing of suitable

wording of the degrees on the scales in various languages.

Other judgement scales are in use concerning the state of various parts of the body (e.g. head, torso,

hands, feet), the total environment or various components of it, other aspects of the experience of

the person or evaluations conducted over a certain period of time, including periods during which-

conditions have not been measured. Other scales, e.g. a bipolar affective evaluation scale, have been

structured differently on the model of perception; such a scale is useful for taking into account pleasure

and is more sensitive than the unipolar discomfort scale in the region near to comfort.

This document is limited to the five scales described in Clauses 4 and 5. The gathering of subjective

judgement should first be concerned with localized sensations (parts of the body) and in constant

conditions, given the current interest and application of these data. The second concern should be for

data gathered under transient conditions, which are extremely important but are not yet sufficiently

well known.
5 Perceptual, evaluation and preferential judgement scales
5.1 Instructions for using the judgement scales

It is important to distinguish between more objective ratings, such as sensations, and affective or

evaluative ratings, such as comfort and pleasure. In everyday language, however, these dimensions are

often confounded and distinctions are not made. In addition, the richness of the semantics for describing

environments and responses to them depends on individuals, their experiences, their language and

their culture, when investigating physical environments. Therefore, it is sometimes useful to first

investigate the psychological dimension (or constructs) which individuals and groups use to describe

[7]
their world .

Two commonly used approaches are semantic differential techniques and personal construct theory

methods. The methods invoke factor analysis or multidimensional scaling techniques to build a

psychological model of the way in which physical environments are perceived and “modelled” (represented

in psychological space) by the person. Similar stimuli on a particular dimension (or all combinations of

dimensions) are placed close together in the multidimensional model of psychological space.

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The form and method of administering the scales are important. For example, a continuous form of the

scale would be to draw a line through all points on the scale where subjective terms are placed. This

would allow a person exposed to the environment to choose values between ratings (e.g. between cool

and cold, a rating of −1,6 on a thermal sensation scale.). In an analysis of the results, this would enable

parametric statistics to be used. However, it is possible that the investigator does not consider that

data are “strong enough” for this and is prepared to use only ordinal data (ranks) and non-parametric

statistics. These, and other, points are of importance and, for further information, the reader is referred

to a text on the design and analysis of surveys and on the use of subjective assessment methods (see [6]).

The psychological interaction when the scale is administered can also influence the results. Usually, the

subjects are given the scale and asked to tick the place which represent “how they feel now”, for example.

It is important to avoid ambiguity, which can lead to a person providing his or her own interpretation,

for example, of what the environment is generally like or how other people perceive it. Other issues

include range effects. The range provided, (e.g. hot to cold) influences the subject’s judgement as do

leading questions: (e.g. “you are uncomfortable, aren’t you?”). The following important issues should be

considered when constructing questionnaires:
— question specificity;
— language;
— clarity;
— leading questions;
— prestige;
— bias;
— embarrassing questions;
— hypothetical questions; and
— impersonal questions.

Other issues include whether knowledge of the results is given. For example, if responses are requested

over time, is the subject informed of previous ratings that he or she made, and whether the ratings are

given in the presence of others? In some circumstances, people can avoid extremes such as end points

on scales or be influenced by the range presented.

Although subjective measurement techniques can be useful for measuring extreme environments, they

should not be used as a primary measure in health and safety. In these conditions, the ability of a person

to make a “rationa
...