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The New Zealand WHOQOL-BREF with national items: Focus group work, item selection, confirmatory factor analysis, and Rasch analysis Chris Krägeloh, Paula.

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Presentation on theme: "The New Zealand WHOQOL-BREF with national items: Focus group work, item selection, confirmatory factor analysis, and Rasch analysis Chris Krägeloh, Paula."— Presentation transcript:

1 The New Zealand WHOQOL-BREF with national items: Focus group work, item selection, confirmatory factor analysis, and Rasch analysis Chris Krägeloh, Paula Kersten, Patricia Hsu, & Joanna Feng Positive Psychology Conference, AUT, Akoranga Campus 8 June 2013

2 Positive Psychology Conference 8 June 2013 Activities of the NZ WHOQOL Group Conducts research in the area of QOL, especially around the WHOQOL tools (WHOQOL-BREF and other modules, such as WHOQOL-SRPB, WHOQOL- DIS, WHOQOL-OLD). We recently validated the WHOQOL-BREF for use in the New Zealand general population. We developed a NZ version of the WHOQOL-BREF, with 5 additional national items.

3 Activities of the NZ WHOQOL Group Monitor the use of the WHOQOL tools in NZ to avoid mis-use. Provide general support and advice on the use of the tools; provide general guidelines on scoring and interpretation. Maintain a current database of WHOQOL data collected in NZ for the purpose of providing reference values for future studies and use in clinical settings. Positive Psychology Conference 8 June 2013

4 The NZ WHOQOL Group in PCRC The NZ WHOQOL Group has recently joined the Outcomes Research Cluster of the Person-Centred Research Centre at AUT. This cluster has demonstrated expertise on the use of outcome measures in health research. Through alignment with this cluster, WHOQOL work in NZ will have access to national and international research networks and contribute to the development and use of outcome measure in health research contexts. Positive Psychology Conference 8 June 2013

5 Purpose of the present talk 1.Background on the initial focus group work for content validation of the WHOQOL-BREF for use in New Zealand. 2.Development of additional optional national items for the WHOQOL-BREF. 3.Validation of the national items: their alignment with the four domains of the WHOQOL-BREF. Positive Psychology Conference 8 June 2013

6 WHOQOL = World Health Organization Quality of Life Scale. Health-related QOL assessment. Developed in the 1990s cross-culturally in 14 countries. Expanded to over 35 country versions since estimate of 123 researchers in 67 centres and 39 countries involved in studies using WHOQOL instruments. Positive Psychology Conference 8 June 2013

7 Rationale behind original WHOQOL development Need for measurement of health beyond traditional morbidity and mortality to include impact of disease and impairment on daily activities and behaviour. Desire to find out what patients and clients felt about themselves to supplement what experts thought. Introduces a humanistic element to health care to balance mechanistic medical approaches. Unsatisfactory and culturally biased translations of similar UK and North American measures. Positive Psychology Conference 8 June 2013

8 Definition of QOL “individuals’ perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards and concerns. It is a broad ranging concept affected in a complex way by the person’s physical health, psychological state, personal beliefs, social relationships and their relationship to salient features of their environment” (WHOQOL Group, 1995) Positive Psychology Conference 8 June 2013

9 Melbourne, Australia Zagreb, Croatia Paris, France Delhi, North India Madras, South India Beersheba, Israel Tokyo, Japan Tilburg, The Netherlands Field centres involved in the development of WHOQOL-100 Positive Psychology Conference 8 June 2013 Panama City, Panama St. Petersburg, Russian Federation Barcelona, Spain Bangkok, Thailand Bath, UK Seattle, USA Harare, Zimbabwe Hong Kong Leipzig, Germany Mannheim, Germany La Plata, Argentina Porto Alegre, Brazil Additional centres involved in the WHOQOL-BREF

10 Properties of the WHOQOL Comprehensive multidimensional profile. Subjective perceptions: “How satisfied are you with your ability to walk?” Objective approach “How well can you walk?” Subjective approach decided upon. Cross-culturally developed with many languages. Standardised 5-point Likert rating scale covering 4 dimensions - intensity (how much), frequency (how often), evaluation (how satisfied), capacity (are you able). Positive Psychology Conference 8 June 2013

11 1.Concept clarification (expert review) 2.Qualitative pilot (incl. focus groups) 3.Developmental pilot (300 questions) 4.Field test (series of studies on smaller scale) Developmental process Positive Psychology Conference 8 June 2013

12 Versions and features WHOQOL-100 = core generic instrument WHOQOL-BREF = abbreviated 26-item version WHOQOL-8 = eight-item version Additional modules = HIV, OLD, SRPB, DIS Some country versions have optional additional national items. Positive Psychology Conference 8 June 2013

13 The WHOQOL-BREF is the most widely used WHOQOL instrument. It is also the most widely used QOL tool in the words.

14 Up until recently, research studies in New Zealand using the World Health Organization Quality of Life questionnaire WHOQOL-BREF have been using the Australian or British versions. In 2008, Prof. Rex Billington and colleagues founded the New Zealand WHOQOL Group. One of the early goals of this group was to validate the instrument for use in New Zealand and thus develop a New Zealand version. Positive Psychology Conference 8 June 2013

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16 Validation of the New Zealand WHOQOL-BREF:  Random sample of participants from the national electoral role to obtain ratings for the existing 26 WHOQOL-BREF items.  Sent out 3,000 questionnaires with self-addressed return envelopes. 710 questionnaires were returned (response rate approximately 24%).  Young people were underrepresented and supplemented by additional purposive sampling, increasing the total number to 808. Positive Psychology Conference 8 June 2013

17 Validation of the New Zealand WHOQOL-BREF:  Conducted confirmatory factor analysis (CFA) with the following specifications:  Promax rotation  Two types of extraction methods:  Diagonally-weighted least squares (DWLS) with polychoric correlations

18 Validation of the New Zealand WHOQOL-BREF The results suggest a good fit: RMSEA=0.072 (criterion for excellent fit <0.060) CFI=0.966 (criterion for very good fit >0.950) SRMR=0.067 (criterion <0.080). Note that, unlike many other studies, a CFA method was used that is more appropriate for Likert-scale data, and this type of method often yields worse fit indices. Nevertheless, the fit indices were comparable (if not higher) than those reported elsewhere. Positive Psychology Conference 8 June 2013

19 Validation of the New Zealand WHOQOL-BREF:  Some ceiling effects for Items 23 (condition of living place) and 25 (transport)  The Rasch model fit the data well and confirmed the CFA results.  There were some issues with DIF (differential item functioning) by demographic variables, and it is recommended to analyse the WHOQOL-BREF domain scores using nonparametric statistics. Positive Psychology Conference 8 June 2013

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21 1. Focus groups and new items  Conducted 13 focus groups with general community members, people with disabilities, and health experts.  These focus groups explored themes about what participants described as elements of QOL.  WHOQOL team also wrote 24 potential new items based on themes that had emerged from those focus groups. Positive Psychology Conference 8 June 2013

22 2. Importance ratings  24 new items were sent out with the WHOQOL-BREF to a random sample of 3,000 participants from the national electoral role.  Participants rated each item in terms of importance.  Candidates for new items with a mean importance rating of <4 were discarded. Positive Psychology Conference 8 June 2013

23  Items were excluded if they exhibited the following:  ceiling or floor effect  low correlation with total QOL and likely parent domain  decreased reliability of the domains  does not discriminate between sick and well  duplicates an existing core item  results in unacceptable CFA fit indices if included Positive Psychology Conference 8 June 2013

24 Items excluded were, for example: How satisfied are you that you eat healthily? To what extent do you feel you have individual freedom? Positive Psychology Conference 8 June 2013

25 Final selected new national items Psychological domain: To what extent do you feel you have control over your life? To what extent are you able to manage personal difficulties? To what extent do you feel respected by others? How satisfied are you that you are able to meet the expectations placed on you? Social domain: To what extent do you have feelings of belonging? Positive Psychology Conference 8 June 2013

26 NB: you can include the NZ national items in domain score calculations. However, as you present them, please make it clear that your scores contain national items.

27 The role of Rasch analysis The outcome measures research cluster has expertise in modern psychometric theories and methods. One of these is Rasch analysis, which we have used in our validation work of the NZ WHOQOL-BREF. It also has many other advantages, as illustrated by the following example: Positive Psychology Conference 8 June 2013

28 Ordinal vs interval measures Toilet Use Dependent □ 0 Needs some help but can do something alone (wipe, undress) □ 1 Independent (on & off, dressing, wiping) □ 2 Feeding Unable □ 0 Needs some help cutting, spreading butter etc. □ 1 Independent (Able to eat normal food served without aid) □ 2 Ruler used with permission from Prof Alan Tennant, Leeds University

29 Ordinal vs interval measures Toilet Use Dependent □ 0 Needs some help but can do something alone (wipe, undress) □ 1 Independent (on & off, dressing, wiping) □ 2 Feeding Unable □ 0 Needs some help cutting, spreading butter etc. □ 1 Independent (Able to eat normal food served without aid) □ 2 Ruler used with permission from Prof Alan Tennant, Leeds University

30 Ordinal vs interval measures Toilet Use Dependent □ 0 Needs some help but can do something alone (wipe, undress) □ 1 Independent (on & off, dressing, wiping) □ 2 Feeding Unable □ 0 Needs some help cutting, spreading butter etc. □ 1 Independent (Able to eat normal food served without aid) □ 2 Ruler used with permission from Prof Alan Tennant, Leeds University

31 Ordinal-level data are problematic The assumptions of ordinal-level data are frequently broken by researchers and health professionals, as ordinal data should not be used in arithmetic operations, such as: –calculation of means –counting up totals –change scores –minimal clinically important difference Under some circumstances, you can come to the wrong conclusion that the patient has plateaued when in fact s/he has not. Rasch analysis can reveal under which circumstances breaking these assumptions can be problematic, and can provide ways to convert these ordinal-level measures to an interval scale. Positive Psychology Conference 8 June 2013

32 Thank you!


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