Scand J Rheumatol 1995; 24: 6I-3

EDITORIAL REVIEW

Cross-cuttural Adaptation and Validation of Heatth Status Measures F. Guillemin School of Public Health, University of Nancy I, France

Key-words: culture, validity, health status measures

In an increasing effort to use standard health status measures internationally, clinicians and medical re- searchers have to face the unknown validity of com- posite measurement tools used cross-culturally. There is a clear need to develop standard procedures to adapt and validate these measures, such as health related quality of life measures. These have generally been developed in a specified culture, often Anglo-Saxon. In this approach, clinicians and researchers have to con- sider the cultural settings in which they intend to use such measures.

Each culture would offer to its member an ideal model of attitudes and reactions in a given society (1). This is also expressed into some cultural specificities regarding health and illness. The culture is important to consider in measuring health status as the perception and expression of ill-health may vary across cultures (2). Besides, the definition and the importance given to health and diseases varies in different health care sys- tems, which are linked to the cultural setting (3). A similar sickness may lead to different consideration by sick persons, by health professionals, or by the society, thus generating different types of care need, of care provision and of sickness benefit. Intercountry compar- isons should use standard measures assessing health status equivalently - rather than identically - over cultural differences.

A distinction should be made between language, culture and country. A cultural setting do not necessar- ily refer to one language nor to one country. Bounda- ries do not respect historical heritage and may some- times separate cultures. A language may be shared by several countries: Dutch language used in2 countries (The Netherlands and Belgium), French is in use in several countries (France, Swizerland, Belgium, Lux- embourg) in Europe and several languages are used in the same country (Belgium). In addition a number of regional dialects are in use within most countries. Problems may also arise from difference in cultural settings using the same language, for example English in the UK and USA. This translates into differences in words, idioms and colloquialism, that are generally

F Guillemin, Ecole de SantB Publique, FacultC de Medecine, BP 184, F-54505 Vandoeuvre-les-Nancy, France Recieved 10 February 1955

understood in another setting, but do not belong to the common language, and may even appear weird.

So, many researchers are challenged with measuring health status and health related quality of life in their own cultural setting. One solution could be to devise a new health status measure best fitting the cultural spe- cificities identified in this setting. Unfortunately, this is a very long and costly process. Moreover, it would give an instrument results of unknown external val- idity, that would not be comparable internationally. Measuring equivalently in different settings is a pre- requisite to measuring comparatively across culture.

Another way is the adaptation of existing measures primarily developed in a different cultural setting. Two steps should be clearly distinguished in the cross-cul- tural development of an instrument of health status to be used in another culture:

- the cross-cultural adaptation comprising of trans- lation in standard language plus adjustment of cul- tural words, idioms and context, possibly involving the complete transformation of some items in order to capture the same concept,

- the validation of the transformed instrument. In the current state-of-the-art, it is not yet clear how far a well cross-culturally adapted instrument keeps its measurement properties. This is not merely because it is difficult to check that the adapted instrument explores the same concept equivalently, i.e. content validity (what it is supposed to do after the adapta- tion process), but also because populations explored are different, especially in many characteristics re- lating in part to culture.

In this issue of the Journal, two papers report on such an approach. Archenholtz et al. (4) have conducted a translation of the AIMS by a translator aware of the concept and the disease, and a back-translation checked with the original. They further conducted a validation study which represent the core of their work. They found that metering properties of the Swedish questionnaire did not all match the properties of the original American questionnaire. Relevantly, they sug- gest that the difference in population involved in their study explain part of these discrepancies. The differ- ences are both in rheumatic disease populations and in cultures. Hedin et al. (5) , in their effort to translate the FIQ, considered socio-cultural differences between

0 1995 Scandinavian University Press on license from Scandinavian Rheumatology Research Foundation 61

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Table I, Guidelines to preserve equivalence in cross-cultural adaptation of composite health status measures*

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Translation Produce several translations Use qualified translators Back-translation Produce as many back-translations as translations Use appropriate back-translators Committee review Constitute a committee to compare source and final versions Membership of the committee should be multidisciplinary Use structured techniques to resolve discrepancies Modify instructions or format, modifylreject inappropriate items, generate new items Ensure that the translation is fully comprehensible Verify cross-cultural equivalence of source and final versions Pre-testing Check for equivalence in source and final versions using a pre-test technique Either use a probe technique Or submit the source and final versions to bilingual lay people Weighting of scores Consider adapting the weights of scores to the cultural context

*Adapted from reference 8

USA and Sweden, especially in employment rate, sick- leave regulations and more generous sickness benefit. This may well condition reactions to ill-health problem and increase health care expenditure (6). They also used a combination of forward and backward trans- lations to produce the Swedish version, then conducted a validation study by examining its metering proper- ties. They carefully evoke the possibility that higher Swedish FIQ score observed may be due to the alter- ation made to the questionnaire during the translation process.

The list of adapted instruments becomes significant now in Europe, underlining the internationalisation and standardisation of research, together with the dissemi- nation of health status measures. However, the fre- quent flourishing production inside each country may be troublesome. Indeed, it might be a major problem when several versions are produced by independent teams in the same cultural settings. A great effort for co-ordination is required in each country to avoid that several different versions of the same measure circu- late and be used for research. Each study should use a referenced version with documented adaptation method and validity, and reject the use of gross trans- lation without a careful adaptation and validation pro- cess.

Cross-cultural adaptation : some guidelines Several methods have been proposed to ensure correct cross-cultural adaptation of complex instruments (questionnaires). They are generally combining several steps of translation, back-translation and expert judge- ment (7). Recent guidelines to preserve equivalence

have been proposed (8). These guidelines represent a synthesis of experiences reported by psychologists, so- ciologists and methodologists in the literature and by experts in the field of health-related quality of life measures:

They recommend the following steps (Table 1): 1) Produce several forward translations using qualified translators native in the target language; 2) Produce as many backward translations as forward translations, conducted independently of each other; 3) Form a committee to compare source and final versions. The role of this committee, which should be multidisciplin- ary, possibly including bilinguals, experts and lay peo- ple, is to ensure that the translation is fully comprehen- sible and to verify cross-cultural equivalence of the source and final versions. This involves semantic (meaning of words), idiomatic (idioms and colloquial- isms or appropriate substitutes), experiential (situa- tions referred to) and conceptual (concept explored) equivalence; 4) Pre-test the final version to check for equivalence with the source version; and 5) Consider adapting the weights of scores (when relevant) to the cultural context.

Because one cannot assess the quality of a cross- cultural adaptation unless one is perfectly bilingual, the checking of these guidelines is the only way to make sure that authors have followed a process agreed on to provide measures with acceptable quality, i.e. that the adapted instrument conveys content equivalent to the original, thus ensuring content validity.

However, it is not clearly established if all steps are essential. In particular, the place and number of back- translations is currently a matter of debate. Each back- translation is intended to reveal or amplify mistakes in each forward translation. But it is argued that the use of back-translation is frequently based on two flawed assumptions (9). The first is that any team would be capable of assessing the proximity or equivalence be- tween source version and back-translation. The second is that forward translation would be fallible, while backward translation would be infallible. So authors propose to put more emphasis on the selection of high- quality translators (forward), on briefing them on the concept they are dealing with, and on involving them in the expert committee.

Cross-cultural validation: several steps to consider Other aspects of the validity, i.e. the metering proper- ties of the adapted instrument should be documented (10). They are not warranted through the adaptation process in the new cultural setting and population but are based on empirical demonstration. A number of terms have been used indistinctly to characterise these properties, leading to a somewhat confusing terminol- ogy. This field of science - assessment of the psycho- metric properties of composite measurement scales - has been developed mainly by social scientists. Be-

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cause no consensus has been reached in the biomedical literature and because some steps are often neglected (1 l), one can propose to use a standard classification made available by the American Psychological Associ- ation (12). One should consider criterion validity, con- struct validity, reliability, and responsiveness by test- ing the adapted instrument in a sample of the target population.

Since validity is the ability of a measurement method to measure what it is intended to measure, it comprises content validity, as well as :

- criterion validity, the quality of the measurement method which corresponds to some other observa- tion that measures accurately the same phenomenon of interest. Such a criterion should be more accurate, i.e. a gold standard, and is frequently not available;

- construct validity is the property of the measurement method which measures accurately the considered underlying construct (that may comprise several at- tributes). This is assessed internally by exploring the factorial validity, when items intended to measure the same attribute correlate better with one another than with items measuring other attributes (factor analysis), and by internal consistency, when several items measuring the same attribute tend to supply the same information and thus to correlate closely with one another. This is also assessed externally: the construct should correlate with related, similar variables measuring the same phenomenon, this is referred to as convergent validity. It should not cor- relate with dissimilar, unrelated ones, what is dis- criminant validity.

- reliability is the ability of the measurement method of being repeatable, i.e. inter-observer and intra- observer reliability. In the case of self-administered questionnaire, only intra-observer reliability is con- sidered.

- sensitivity to change or responsiveness is the power to detect a change in the measured phenomenon in individuals or groups.

Cross-cultural adaptation and validation is a long but cost-effective process. It is important to acknowledge that beyond the apparent simplicity of scores, the con- cept of health status is not simple to capture, the in- strument developers have devoted a great effort to elicit the core of relevant concepts (conceptualisation, construction, validation, and revision) and the interpre- tation of these scores is not always straightforward. The adaptation should keep equivalent the material issued from previous work and preserve all aspects of its validity.

Importance in clinical epidemiology The conduct of large international clinical trials re- quires that a similar measure be applied equivalently across settings. Thus the equivalence of these measure

is a prerequisite to such studies, as well as to cross- national comparison of study results. It would be a nonsense to compare effect sizes of a drug from differ- ent studies using not comparable measures. Also, the importance of measuring these determinants equiv- alently has been stressed in the analytic approach, i.e. case-control or cohort studies, to identify risk or prog- nostic factors of a disease (3).

Importance in health service research Similarly, it is preferable not to introduce additional variability to national differences in health services research. For that reason, comparison of diseases or services across several health care systems should avoid cross-cultural discrepancies in the measurement method. This would also help to preserve the internal validity in direct cross-national and cross-cultural com- parison of international researches, and the external validity, i.e. understandability to foreigners, of national researches.

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Zborowsky M. Cultural components in responses to pain. J SOC Issues 1952; 8: 16-30. Kleinman A, Eisenberg L, Good B. Culture, illness and care: clinical lessons from anthropologic and cross-cultural research. Ann Intern Med 1978; 88: 251-8. Helman CG. Culture, health and illness. 2nd ed. London; Wright 1990, 344 p. Archenholtz B, Bjelle A. Evaluation of a Swedish version of the arthritis impact measurement scales. Scand J Rheumatol 1995;

Hedin PJ, Hamne M, Burckhardt CS, Engstrom-Laurent A. The fibromyalgia impact questionnaire, a Swedish translation of a new tool for evaluation of the fibromyalgia patient. Scand J Rheumatol 1995; 24: 70-77. Lee P. The economic impact of muskuloskeletal disorders. Qual. Life Res. 1994; 3: 585-92. Bullinger M, Anderson R, Cella D, Aaronson N. Developing and evaluating cross-cultural instruments from minimum re- quirements to optimal models. Qual. Life Res. 1993; 2: 451-9. Guillemin F, Bombardier C, Beaton D. Cross-cultural adapta- tion of health related quality of life measures: literature review and proposed guidelines. J Clin Qpidemiol 1993; 46: 1417-32. Leplege A, Verdier A. The adaptation of health status measures. A discussion of certain methodological aspects of the trans- lation procedure. In: Shumaker S, R Berzon, eds. The internal assessment of health-related quality of life: Theory, translation, measurement and analysis. Oxford; Rapid communications of Oxford, 1994, 178 p. Streiner DL, Norman GR. Health Measurement scales. A prac- tical guide to their development and use. Toronto; Oxford Medical Publications. 1989, 175 p. Coste J, Fermanian J, Venot A. Methodological and statistical problems in the construction of composite measurement scales: a survey of six medical and epidemiological journals. Stat Med 1995 (in press). American Psychological Association. Standards for Educa- tional and Psychological Tests, Washington, DC; American Psychological Association, 1985.

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