Translation and Cross-Cultural Equivalence of Health Measures

1. Translation and Cross-Cultural Equivalence of Health Measures

2. Context • Multinational companies & international drug trials • Cross-cultural research within Canada • International health studies • General sense of globalization – but does this downplay differences?

3. Relevance of Culture • Culture shapes the way we conceive of health and illness • Influences customary behaviours, relationships with others • Influences relative values of symptoms • Reactions to pain, etc. • Expectations & definitions of feeling good, etc. • ‘Questionnaire sophistication’ of the group

4. Level of abstraction • Concepts can be: • Abstract and general • Happiness, Ability • Concrete and specific • Number of hospital beds per capita • More abstract concepts • Applicable to different cultures, but • More imprecise • Specific concepts • Less cross-culturally applicable • More context dependent

5. Types of Cross-Cultural Equivalence • Is it operationalized in same way? (Same general measurement procedures) • Item equivalence: Items should mean the same thing to people in one culture as in another • Scalar equivalence (E.g., is the distance between “moderately severe” and “severe” the same in both cultures?)

6. Requirements for cross-cultural equivalence • Conceptual/functional • Equivalence in construct operationalization • Item equivalence • Scalar equivalence • Hierarchical: must have first before second

7. Conceptual/FunctionalEquivalence • Is there a universal situation? • Does construct mean the same thing in both cultures? • Can goal of behaviour be identified? • Are same antecedent-consequent relations demonstrable across cultures? • Does same situation result in same behaviour across cultures?

8. Equivalence in operationalization • Is it operationalized in same way? • Same procedure • E.g. measuring disability with • Questions on self-care • Measuring visual impairment with • Snellen chart

9. Item equivalence • Measured by same instrument • Items should mean the same thing to people in one culture as in another • E.g. on FAS test, items with identical meaning in French are not FAS, but T, N and P • “No ifs, ands, or buts”

10. Scalar Equivalence • Measured on the same metric • Numerical value on scale has same degree of intensity or magnitude of the construct • E.g. is the distance between 6 (moderately severe) and 7 (severe) the same in both cultures?

11. Developing cross-cultural measures • Sequential approach • Translate an instrument into another language • Simultaneous approach • Conceptualize & develop measure in each culture • Set of equivalent items that reflect the same construct in different cultures • Core instrument plus culture-specific additional components

12. Strategies for ensuring cross-cultural equivalence • Direct translation and comparison • Better translation techniques • Multi-trait, multimethod • Item response theory methods • Differential item functioning

13. Strategies: continued • Response pattern method • Factor analysis • Multidimensional scaling • Combined etic-emic approach • Multi-strategy approach

14. Methods for assessing equivalence • Factor analysis • Empirical analysis of how items relate to one another • Shows how many concepts scale measures and which items measure that scale • Confirmatory: must have theory about how items go together • Simultaneous factor analysis in different populations • Factor structure should be the same • Test whether data are similar to be called equal • Same factor pattern-loadings • Same goodness of fit

15. Differential item functioning • Related to IRT theory • Needed because tests can have matching factor structures and still be biased • DIF analyses • Compare reference and focal groups • In translation from English to French, English reference and French focal

16. Differential Item Functioning • DIF = a different in item score between two groups who are equal in ability. • First step: match on ability (total score) • Internal test of item bias • 2nd step: for each score group, compares performance of reference and focal group on each item

17. Two types of DIF • Uniform • Difference in difficulty between reference and focal group • Item may be more difficult for one group • Non-uniform • Difference in discrimination between reference and focal group

18. When you find DIF or non-factorial equivalence • Study reasons why • Content experts • Review item wording, translation, cultural meaning.

19. Translation • Simply translate instrument and administer it • Simple tests of difference: assumes scalar equivalence • Translation-back translation

20. Issues to Consider • Goal: to adapt measure for a new country, or to make comparisons across countries? • Translation or adaptation? Back-translation gives identity rather than equivalence • In most countries the ‘official’ language differs from the vernacular. Which do we use? • We still know little about effect of linguistic variations within countries

21. Issues - continued • Why was this instrument chosen? Are these features relevant in another culture? • At least some of the content of most scales will be culture-specific (e.g., some of NHP seen as blasphemous in Arabic countries) • Was the scale developed on a particular cultural group?

22. Quality of Life • Quality of life is subjective & value-specific • Invented in the USA; ¿not universal? • Definition will at least vary across cultures (naïve enthusiasm for QoL) • Handicap reflects impairment + environment, so measures may perform differently in different environments

23. Translation, or Domination? • “…with refinements and changes introduced here and there in order to convey the meaning of the English questions as accurately as possible…” (A. Leighton)

24. Words & Concepts • An etic approach (phonetic) describes the physical properties of the word, without referring to its functional meaning: language • The emic approach takes account of the context, meaning and purpose of the word: concepts

25. Translation Example • “Does poor health prevent you from seeing your friends?” • Meaning of “friend” differs in UK, US, and Australian English • Even more differences between Ami(e), Amigo and Freund

26. Suggestions • Plan cross-cultural applications from the outset • Consider relevance of quality of life carefully: omit? • Avoid questionnaires! • Use ‘DIF’ analyses • Run within-country analyses • Develop measures within each country • Seek core set of universal items (WHO QoL) • Make sure the values are explicit